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VTeixeira
05-28-2010, 04:58 PM
I've placed this question in another forum but related with FumeFx.
It seems that this dissolve effect is more related to particles.


http://www.youtube.com/user/bank508max

Hope someone can tell me something.
I've been searching and I find this tutorial from Allan but my objective is to make it based on an image.
http://vfxsolution.com/allanmckay/2009/11/legacy-fx-tutorials/
Cheers

Glacierise
05-28-2010, 05:36 PM
Read about camera projection with krakatoa in the krakatoa thread ;)

VTeixeira
05-28-2010, 06:49 PM
I'll do that.
Thanks


Is this the one you were talking?
http://software.primefocusworld.com/software/support/krakatoa/camera_mapping_particles_using_dataflow.php

VTeixeira
05-29-2010, 12:30 AM
In Maya I remember we can project via nparticles the image.
I though we could do something similar here.
Instead of making this to the geometry I would do it to the image.
Is this possible? Dissolve an image?

Bobo
05-29-2010, 12:40 AM
I'll do that.
Thanks


Is this the one you were talking?
http://software.primefocusworld.com/software/support/krakatoa/camera_mapping_particles_using_dataflow.php

Nope.

This is old and more for amusement, plus it uses Box #3 or MAXScript.

This tutorial, although over a year old, gives the basic idea:
http://www.studiodaily.com/studiomonthly/tutorials/trainup/Disintegrate-Geometry-Objects-using-Frantic-Films-Krakatoa-and-Autodesk-3ds-Max_10691.html

In the CGTalk Krakatoa thread, I posted an updated workflow description about 2 days ago. It would be very useful to you to read what is being posted in that thread.
http://forums.cgsociety.org/showpost.php?p=6522542&postcount=1087

Also, particles with camera projection on them ARE like the pixels of an image, but in 3D.
So there is no need to work on an image when you can use the particles as canvas for your images and do anything with them.

VTeixeira
05-29-2010, 05:17 AM
Also, particles with camera projection on them ARE like the pixels of an image, but in 3D. So there is no need to work on an image when you can use the particles as canvas for your images and do anything with them.

That's exactly what I was thinking.
So theres no need for me to create any geometry right?
I asking because the method I was thinking of using was to create the face in 3D and then dissolve from that.

Bobo
05-29-2010, 07:02 AM
That's exactly what I was thinking.
So theres no need for me to create any geometry right?
I asking because the method I was thinking of using was to create the face in 3D and then dissolve from that.

In these examples, you use both. The polygon model was used to render the projection image, then the particles were distributed onto the geometry's surface. So the geometry was used in the process, just not directly.

VTeixeira
05-29-2010, 12:41 PM
But still If I have an image in motion, like a face in my case, I have to have a geometry model for it?
Thanks Bobo

Bobo
05-29-2010, 03:57 PM
But still If I have an image in motion, like a face in my case, I have to have a geometry model for it?
Thanks Bobo

Depends.
You can project an image of a moving face onto any particles. But if you want the particles to have the 3D shape of that face, you would need its 3D mesh. For example, the car examples you see are generally created by taking a 3D mesh of the car, placing particles on all surfaces and projecting a rendering of that mesh through the same camera used in the particle rendering, but using something like mental ray of VRay or Scanline etc. This gives you a 2D image of the 3D mesh that matches what the Krakatoa camera would see, and each pixel of the 2D image lands on a 3D "pixel" (particle) in 3D space. The color of that pixel sticks to the particle so if the particle moves around in 3D space due to Wind or other forces, the color is still the same as if the particle did not move. This produces the effect of the image dissolving because the particles move but their color stays the same according to the projection.

Here is the very first example of the effect created before Krakatoa was even called Krakatoa:
http://software.primefocusworld.com/software/support/krakatoa/work_in_progress_gallery.php#Mini_Cooper_Demo

Notice how all raytracing effects like reflections in the windshields etc. are still in tact even when the particles start moving...

VTeixeira
05-29-2010, 04:05 PM
Now I get it.
The geometry of the mesh is completely necessary.
I was hoping not but I have to build the face and the animation corresponding to the image sequence. Some extra work but it will look great thanks to what you said before.
A huge thanks Bobo.
Really appreciate all the help.
I'll post any further doubts or problems her.
Hope I can post some tests soon.
I'll work on that.
Cheers

VTeixeira
05-29-2010, 09:57 PM
Bobo I think I'm going to try that dissolve effect but in 2D.
When I say 2D there are some considerations that I don't know the answer.
Has I'm going to try to dissolve a face I wanted to ask you if I could use a plane for example.
His it possible that he could recognize an image with alpha channel?
Thanks

Bobo
05-30-2010, 01:36 AM
Bobo I think I'm going to try that dissolve effect but in 2D.
When I say 2D there are some considerations that I don't know the answer.
Has I'm going to try to dissolve a face I wanted to ask you if I could use a plane for example.
His it possible that he could recognize an image with alpha channel?
Thanks

Yes, that should be easier.

*Create a plane.
*Convert to particles - either using a PRT Volume or using PFlow.
*Align a Free Camera to the Plane to project the image onto the plane of particles
*Assign a Material to the particles using Standard Material with Camera Map Per-Pixel map in the diffuse slot.
*Pick the new camera in the Camera Map Per Pixel map
*If the image is a sequence of images (animation), check the "Sequence" checkbox in the Bitmap texture map when loading to turn into an IFL so the animation would get projected over time
*Repeat the same for the Opacity channel, using the Alpha of the image sequence - this will control the Density of the particles so where alpha is 0, the particle won't render.
*Now use Krakatoa to save these particles to disk as PRT sequence, including Position, Color and Density channels.
*Load this sequence into a new PRT Loader
*Create a Particle Flow with Krakatoa PRT Birth and Krakatoa PRT Update operators picking the PRT Loader. Check the Color channel to be loaded. (for the Density, we will have to do some more work though).
*Apply forces to the particles to dissolve the plane - the colors saved in the PRT Sequence will stick to the particles though.

As mentioned, the Density does not go into PFlow directly because it has no concept of Density. Thus, we will have to add a KCM on top of the PRT Loader, switch the Input node to Density channel, switch the Output channel to MXSFloat and make sure the MXSFloat input is checked in the Krakatoa PRT Update operator of the PFlow. Now add a Krakatoa Options operator and check "MXSFloat->Density". This tell Krakatoa to read the MXSFloat channel we just copied the Density to as the Density at render time.

This setup will require a light to illuminate the particles, otherwise you will get black. If you prefer to render without lights, you can add a global override KCM in the Krakatoa Render Globals rollout and copy the Color channel into the Emission channel, then enable Use Emission. This will make the particles self-illuminated with the color saved in the Color channel we projected and saved previously...

Note that this is all from top of my head, I have not tried it out yet and it might not work in some points - if you hit a wall, post here. I might try it out after dinner...

VTeixeira
05-30-2010, 03:32 AM
Don't know how to thank you bobo.
Fantastic.
Here in Portugal is 3.30 AM
I'll try this right in the morning.
I'll post any doubts I may have.
A huge thanks bobo.
I definitely owe you not one but twenty or fifty.
Talk with you soon.
Cheers

Bobo
05-30-2010, 04:50 AM
Don't know how to thank you bobo.
Fantastic.
Here in Portugal is 3.30 AM
I'll try this right in the morning.
I'll post any doubts I may have.
A huge thanks bobo.
I definitely owe you not one but twenty or fifty.
Talk with you soon.
Cheers

I just went through the whole process and it works as described. Good luck!

VTeixeira
05-30-2010, 01:51 PM
Thanks Bobo.
I'll post my test in a moment.
Cheers

VTeixeira
05-31-2010, 05:47 AM
Hello Bobo,
first I would like to thank you for the amazing guide you give.
The only thing I couldn't do was this:
copy the Color channel into the Emission channel, then enable Use Emission. This will make the particles self-illuminated with the color saved in the Color channel we projected and saved previously...

I have a few doubts about this process.
In terms of particles it looks strange as you can look in the image cause I was expecting in getting it clearly. I increased a lot the number of particles don't know why it looks like this way - small dots. I've noticed that when I'm rendering the particles I'm loosing the image. Should I render this with scanline or krakatoa? I'm not quite understanding the process for the final rendering.

My other question is related with the size of the image. My image is 640*480. How can I do the correct resolution when I'm creating a plane and transforming it to .prt Volume?

I used a wind force perhaps not the best choice to disperse the particles.

I'm going to bed but I'll do this again and I'll post my scene file with an single image for you to understand better my doubts.
If you don't mind Bobo.

Bobo
05-31-2010, 06:11 AM
In the Global Render Values rollout, press "Create New Global Override Set" and edit the resulting MagmaFlow to output the Color channel (already set as input) to the Emission channel (in the output node). Then check ">Use Emission" in the Main Controls rollout.

You are supposed to render as particles in Krakatoa (or as voxels, if you have to, but that will produce less obvious image). You will need a relatively high particle count to get a solid looking plane, but it depends on the distance from which you are watching and the final resolution of the particle rendering. About a million particles at least.

Since the image is being projected using a Camera Map Per Pixel map and all particles with Alpha 0 will not be rendered, it doesn't matter much what the aspect of the plane/particle system is as long as the camera projects on the particles.

I also used a turbulent Wind space warp and with the right settings it can look pretty good, although a FumeFX sim would look a lot more "physically correct".

I am not sure where the renderer confusion comes from - you render the image to be projected in whatever renderer you want (Scanline, mental ray, VRay) and the particles in Krakatoa. It IS possible to render particles as meshes in Scanline, but then you would need some sort of shape mesh on each particle and it will be slow, plus it would require some Vertex Color maps in a Standard Material to make the saved colors visible...

Hope this answers your question somewhat. If not, continue posting.

VTeixeira
05-31-2010, 01:07 PM
Since the image is being projected using a Camera Map Per Pixel map and all particles with Alpha 0 will not be rendered, it doesn't matter much what the aspect of the plane/particle system is as long as the camera projects on the particles.

Ok ok it makes sense. I have to define that in the rendering camera settings to the proper resolution. I don't have this clear in my head cause of Maya. I've started to ork within Max without studying the basics. What as been helping me his a plugin from digital raster that passes some shortcuts from maya to max.

When you talk about aligning the camera the only thing I did was to place it, at the origin in the top view looking down. This is right correct?

but it depends on the distance from which you are watching and the final resolution of the particle rendering. About a million particles at least.
I made 10 partitions probably I'll need more..

I'll post my scene file and some imagens of my next test.
Once again THANK YOU

Bobo
05-31-2010, 03:04 PM
Ok ok it makes sense. I have to define that in the rendering camera settings to the proper resolution. I don't have this clear in my head cause of Maya. I've started to ork within Max without studying the basics. What as been helping me his a plugin from digital raster that passes some shortcuts from maya to max.

When you talk about aligning the camera the only thing I did was to place it, at the origin in the top view looking down. This is right correct?


If the plane and the resulting particles are at the origin in the horizontal plane, then a camera placed above them would work. Basically imagine the Camera were a Projector that sends the color information to the particles.


I made 10 partitions probably I'll need more..

Are you using a PRT Volume or PFlow to create the particles? If you are using PRT Volume, partitioning won't work - just increase the number of particles per voxel. If you are using PFlow with Position Object operator, then more particles per partition and more partitions are both ok ideas.

I will try to write a short tutorial with screenshots later today.

VTeixeira
05-31-2010, 03:57 PM
Are you using a PRT Volume or PFlow to create the particles? If you are using PRT Volume, partitioning won't work - just increase the number of particles per voxel. If you are using PFlow with Position Object operator, then more particles per partition and more partitions are both ok ideas.

I've started using a PRT Volume.
That's why I couldn't increase the number or the detail related with the particles.
I used the PRT Volume cause I wasn't sure how to transform the plane into particles.
I think the process is exactly like in this tutorial right?
http://software.primefocusworld.com/software/support/krakatoa/basic_particle_rendering_tutorial_demo_file.php
Where you change the teapot by particles.
Right?

Bobo
05-31-2010, 04:56 PM
I've started using a PRT Volume.
That's why I couldn't increase the number or the detail related with the particles.
I used the PRT Volume cause I wasn't sure how to transform the plane into particles.
I think the process is exactly like in this tutorial right?
http://software.primefocusworld.com/software/support/krakatoa/basic_particle_rendering_tutorial_demo_file.php
Where you change the teapot by particles.
Right?

Right. A PFlow with a default Position Object Operator distributes particles randomly on the surface.
You could even use a planar emitter and no plane at all (you don't really need geometry to make a plane out of particles since the default PFlow already creates a planar distribution - the size controls are in the Emitter).

In a PRT Volume, you can change the number of particles with its controls without the need for partitioning. If using Regular Grid mode, change the Subdivisions value (2 means 8 times more particles - 2x2x2, 3 means 27 times more particles and so on). If you are using Random In Cube, the Number value controls the actual count per voxel. Finally, the Spacing value controls the Voxel Size and thus the base number of particles, too, but it is a bad idea to decrease that one because it eats up more memory.

VTeixeira
05-31-2010, 05:41 PM
Here is my scene file in two steps.
I'm having problems related with the forces.
Don't know which one is better to apply and create that dissolve, "smoke trail" from left to right, effect.
In here that same resolution problem maintains because I didn't see your last post.

http://www.sendspace.com/file/4a5blp

Hope you can see it.
I'm now rendering it. I've used that >Use Emission option but I only see an image when, after rendering, I activate the alpha.
Cheers

Bobo
05-31-2010, 06:00 PM
Here is my scene file in two steps.
I'm having problems related with the forces.
Don't know which one is better to apply and create that dissolve, "smoke trail" from left to right, effect.
In here that same resolution problem maintains because I didn't see your last post.

http://www.sendspace.com/file/4a5blp

Hope you can see it.
I'm now rendering it. I've used that >Use Emission option but I only see an image when, after rendering, I activate the alpha.
Cheers

I cannot use file sharing sites from the office (IT policy). Will try tonight from home.

Did you copy the Color channel into the Emission channel as instructed using a MagmaFlow?

VTeixeira
05-31-2010, 06:39 PM
It's ok Bobo.
Well this was what I've done:
Probably something is wrong.

Bobo
05-31-2010, 08:49 PM
It's ok Bobo.
Well this was what I've done:
Probably something is wrong.

That is correct for copying the Density into the MXSFloat.
But you need to add a SECOND KCM (press the Add button, change output from Color to Emission) to copy the Color into Emission channel to turn the particles into self-illuminated (emissive) ones.
You can have any number of KCMs in that Override Set.

Bobo
05-31-2010, 08:51 PM
Btw, if you are using the PRT Volume approach, the PRT Volume will acquire various channels including the Texture Mapping Coordinates. So assigning a material with a bitmap texture to the PRT Volume will color the particles immediately. Thus you don't need to use Camera Map Per Pixel in that simple case. The Camera Mapping makes sense when you are rendering through a perspective camera and want to project a Scanline or mental ray rendering onto the particles in Krakatoa through the same camera. But for an image dissovling into points, just using a plane, PRT Volume and a material with a bitmap will be enough to create the basic PRT files before you animate them in PFlow.

VTeixeira
05-31-2010, 09:28 PM
But you need to add a SECOND KCM (press the Add button, change output from Color to Emission) to copy the Color into Emission channel to turn the particles into self-illuminated (emissive) ones. You can have any number of KCMs in that Override Set.
I do this after what you saw you in my attachments right? Or after that process you described a few posts ago?
Sorry for asking but how can I had a SECOND KCM?



So to achieve somthing similar to this:
http://www.youtube.com/user/bank508max

I should use an particleFlow instead of an PRT Volume at the begining?
I know this is 3D and my objective is "2D" but this is just an example in terms of look.

Bobo
05-31-2010, 09:42 PM
So to achieve somthing similar to this:
http://www.youtube.com/user/bank508max

I should use an particleFlow instead of an PRT Volume at the begining?
I know this is 3D and my objective is "2D" but this is just an example in terms of look.

No, to achieve this, you
*Render in Scanline or mental ray from the given camera
*Use PFlow to distribute particles onto the mesh and project the images rendered in the previous step using Camera Map Per Pixel
*Save to PRT sequence
*Load in PRT Loader
*Load into a new PFlow and blow them away

In this case you don't have to deal with the Density channel at all because there are no particles in the scene that do not get a full Alpha image.

I was talking about your quest to blow a 2D plane with an image on it. In that case, if the image contains alpha channel and not all pixels are alpha > 1.0, you

*Create a Plane
*Assign a material with a bitmap texture containing the image or image sequence in the Diffuse AND Opacity map slots
*Create a PRT Volume and assign the same material - particles will show the same image if "Show Maps In Viewport" is checked.
*Save to PRT sequence - Density channel will contain 1 for colored particles and 0 for particles with Alpha = 0
*Load in a PFlow and blow away (including all the tricks for getting the Density info over).

I am not sure if the language barrier is the problem here, or I am not explaining myself correctly.
Try to understand the PRINCIPLE behind it, not the exact steps. There are several ways to skin a cat in Max and Krakatoa, and you don't have to remember what I am doing, but WHY I am doing it.

Bobo
05-31-2010, 09:44 PM
Sorry for asking but how can I had a SECOND KCM?


See that "Add..." button in the Global Render Values rollout underneath the KCM list that shows ==base object== and the first KCM? Press it and a NEW modifier with its own flow will be created. Change that flow, now you have both Emission and Density global overrides.

Bobo
05-31-2010, 10:09 PM
I am writing a detailed tutorial with illustrations to post on the Krakatoa documentation page later today. Stay tuned.

VTeixeira
05-31-2010, 10:26 PM
It will probably be best.
Really appreciate that Bobo.
I'll stay tuned.

The language it's not a problem really. The main problem is my lack of experience with Max. That is the major problem but I'm persistent and I'll do this the right way.

I was talking about your quest to blow a 2D plane with an image on it. In that case, if the image contains alpha channel and not all pixels are alpha > 1.0, you

At the moment my main objective is to create that effect like in the video I post before but based in a 2D plane cause the person I'm working doesn't have the time to create the animated face in 3D and to track it exactly like in the image sequence. So I'm working directly on the image sequence, following what you are saying.

Bobo
06-01-2010, 12:19 AM
I finished the example of dissolving an image plane.

http://software.primefocusworld.com/software/support/krakatoa/image_plane_dissolve.php

It will look similar to the car animation, but it does not involve 3D particle distribution - the car and the particles in that example were actually in 3D and that required camera mapping. For an image plane, the UVs are already there and you can map ANY animation to the plane and look at it from any angle, then convert the pixels to "3D pixels = particles"...

I used a simple teapot animation (bending from 0 to 180 degrees just to show some motion) and used a Wind to blow the particle plane away as usual... Particles that would normally show the black background were set to Density (Alpha) of 0 so they did not render - I set the Krakatoa background to blue to demonstrate that.

Note that the demo images I rendered were under a certain angle to the plane, so this produced double-transformation in the perspective. Normally, you would align the plane to the camera's image plane to you would render the particles frontally.

JohnnyRandom
06-01-2010, 12:52 AM
That is pretty sweet technique, from the pics it actually gives the illusion of some depth too. Nice Work :)

VTeixeira
06-01-2010, 04:19 AM
I definitely have to say you are the man.
Don't know how to thank you Bobo.
Really I don't.
The best thing I can do at the moment is to test it.
I'll try to increase the number of particles to get that ink or smoke look.
I'll post my results in a couple of few hours.
Huge thanks once again Bobo.
This is fantastic.

Nickolay411
06-01-2010, 05:33 PM
I just went through the whole process and it works as described. Good luck!

lol thats great.

Glacierise
06-01-2010, 05:47 PM
The most comprehensive help on forums I've seen :) Bobo should be paid :)

Bobo
06-02-2010, 12:34 AM
The most comprehensive help on forums I've seen :) Bobo should be paid :)

Newsflash: I am being paid. It is part of my job, even have a field in the time sheet for Krakatoa Support. When supporting prospective customers, it is a form of advertising :)

VTeixeira
06-02-2010, 01:31 AM
I'm glad you are.
You really deserve it.
I'm still testing but my problems at the moment are related with the increase of details Bobo.
Don't know how many partitions should I do to get that ink look to the dissolve.
Won't I loose detail in the image if I mess around with the density in the krakatoa?
Probably that can be fixed within post production.
Well still testing

Glacierise
06-02-2010, 07:22 AM
... and it works! Cheers!

Bobo
06-02-2010, 02:22 PM
Don't know how many partitions should I do to get that ink look to the dissolve.


Well, unfortunately, the setup I posted does NOT support partitioning at any stage of the process, unless your final PFlow contains an operator with a Random seed (mine doesn't).

In order to be able to partition something, you need a random factor that is controllable by MAXScript - usually these are the Position Operator, the Speed Operator, the Spawn Operator and so on. The PRT Volume itself cannot be randomized (it will be possible in v1.6.0 but not now), and the PFlow I used was loading explicit positions from a saved file, so that cannot be randomized either. The Force operator I applied the Wind with doesn't support randomization. I am not sure if the FumeFX operator you might be using can be randomized.

But in general, if you want more particles, you should be making more particles in the PRT Volume. This of course will slow down the PFlow a lot, but I assume it will work for around 10 million particles (I was using only a million in the second run of the example).

If you could post details about your setup and where exactly you expect the Partitioning to make changes to the system, it would be helpful. As it is now, if you don't have anything with a random seed, all partitions will end up exactly the same and no new detail would be introduced. At least that's the case in the setup I illustrated on our site.

VTeixeira
06-02-2010, 02:29 PM
I'll finish the tutorial and post the example.
My main concern is to get a lot of detail in the particles that get dissolved.
Just like in the videos I've shown you before.

Bobo
06-02-2010, 04:35 PM
I'll finish the tutorial and post the example.
My main concern is to get a lot of detail in the particles that get dissolved.
Just like in the videos I've shown you before.

I understand that. So I am proposing the use of "Random In Cube" mode of the PRT Volume to save out a very large amount of particles with random positions within the PRT Volume's voxel grid. Then you could reduce the Density multiplier (since you will have a lot of particles occupying the same pixel if the particle count is high enough), and because the initial particle positions will be slightly different, the influence of the forces in PFlow will drive them differently.

Alternatively, you can create a single PRT sequence from the PRT Volume and add a Noise Modifier to the PRT Loader with a very very small Strength along X,Y and Z and a very small scale (around 1.0). When you pick that PRT Loader in the PFlow, the randomization of particle positions will be taken into account by PFlow and you can use the Partitioning functionality to produce any number of sequence that will be slightly different. (just check the PRT Loader Modifiers option in Partitioning rollout to look for that Noise).

The drawback of this approach is that shifting the particles randomly with the Noise modifier will shift the "3D pixels" in 3D space but the colors will stick to them, so if the shift is larger than one pixel of the final image, you might start getting blurring in the rendered image.

On the other hand, when using Random In Cube mode in the PRT Volume and creating one big PRT with all particles, each random position will sample the color of the mapped image correctly. The drawback is that the PFlow would be much slower to process as it would have to run all particles at once.

VTeixeira
06-02-2010, 05:57 PM
I'll start doing this right away.
Talk with you soon Bobo.

JohnnyRandom
06-02-2010, 06:56 PM
Won't I loose detail in the image if I mess around with the density in the krakatoa?


Of course! but if you have a sufficient amount of particles the only detail you loose is detail you don't want anyway. :) ie single particle or low density clusters be gone, leaving a detail rich core with some nice feathered edges.

VTeixeira
06-04-2010, 04:31 AM
I understand that. So I am proposing the use of "Random In Cube" mode of the PRT Volume to save out a very large amount of particles with random positions within the PRT Volume's voxel grid. Then you could reduce the Density multiplier (since you will have a lot of particles occupying the same pixel if the particle count is high enough), and because the initial particle positions will be slightly different, the influence of the forces in PFlow will drive them differently.

I've decided to follow this direction Bobo.
I placed the number 20 in here. What does this number represents? Millions? Thousands? The render of 40 frames took me 4 hours.
I'm glad I finished it.
I'm still testing some new ways to make the particles fly away. Cause my main interests is to make them create a certain type of "death eaters" smoke trail.
My idea is to reverse it and perhaps try to mix it with FumeFx but thats another conversation.
My main concern at the moment is to achieve the best quality possible and to increase the number of particles to the max I can get. so that's why I'm asking about what thins value means in the "Random in Cube".

I talked recently about partition Bobo because my idea was to create the max number of particles possible to achieve that smoke look.
Cheers

Bobo
06-04-2010, 03:08 PM
I've decided to follow this direction Bobo.
I placed the number 20 in here. What does this number represents? Millions? Thousands?


The Random In Cube value defines number of PARTICLES per voxel.
See the following topic in the Help:
http://software.primefocusworld.com/software/support/krakatoa/prt_volume_grid_and_random_particle_generation.php

In the first part, the right column shows how a PRT Volume voxelizes the mesh and then places a particle in the middle of each voxel (this is Regular Grid mode with 1 subdivision).

In the case of Random In Cube, when the Number value is 1, one particle is once again placed in each voxel, but it is not in the center but pseudo-randomly distributed inside the voxel. When you increase the Number to 20, 20 particles will be seeded in each voxel.

So the final count depends on the size of the Voxel (which is controlled by the Spacing value) multiplied by the Number value when using Random In Cube.

When using Regular Grid though, the subdivisions increase the number exponentially by the power of 3, so a value of 3 produces 27 particles per voxel, all neatly ordered in a grid of 3x3x3 inside the voxel.

VTeixeira
06-04-2010, 03:49 PM
Until what value do you think it's reasonable to place the spacing, at this moment I'm at 0.5, and the number in the Random in Cube, that is 20?

I'll probably try to increase it a little bit more.
Thanks Bobo

Bobo
06-04-2010, 04:05 PM
Until what value do you think it's reasonable to place the spacing, at this moment I'm at 0.5, and the number in the Random in Cube, that is 20?

I'll probably try to increase it a little bit more.
Thanks Bobo

In the Channels rollout (or by right-clicking the PCache button, or by looking into the Krakatoa Log window), you can see how many particles were actually generated at render time. The Spacing means nothing without knowing the size and shape of the object. If it is a plane, it depends on the width and length of the plane. Multiply the width*height by the spacing and you will get an idea about the number of voxels in two dimensions. Keep in mind that the PRT Volume might add several voxels thickness because a plane is open and it uses some spacing around the bounding box to solve that. (see the topic http://software.primefocusworld.com/software/support/krakatoa/render_geometry_volumes.php#Filling_Partially_Open_Objects for details)

So it depends on your geometry, the resulting number of particles at render time and your workstation's RAM, not on what I say is a good number ;) The Channels rollout has a Memory/Count calculator to help you figure out how many particles could fit in a specific amount of RAM. Once you know the current count, you can add more particles by increasing the number value or changing the Spacing (smaller Spacing values -> more voxels -> more particles).

VTeixeira
06-04-2010, 04:21 PM
The Channels rollout has a Memory/Count calculator to help you figure out how many particles could fit in a specific amount of RAM
Where can I find this Bobo?

My main concern at the moment is that because of the values I placed in I can't get the entire image cause my computer almost crashes. I'm only able to see a small portion. So I'm orienting myself by the plane that has the material of the image. My main concern is because I can't see the movement the particles after I place the forces to make the dissolve.
The only thing I can do is to do a lower the number of particles and then apply all the forces, right? -and them pass this to the higher version.
I don't see any other way


My plane is 288 by 512 in generic units.
The image size is 1152 by 2048.
Cheers

Bobo
06-04-2010, 04:35 PM
Where can I find this Bobo?
In the Krakatoa UI, where else?


My main concern at the moment is that because of the values I placed in I can't get the entire image cause my computer almost crashes. So I'm orienting myself by the plane that has the material of the image. My main concern is because I can't see the movement the particles after I place the forces to make the dissolve.
The only thing I can do is to do a lower the number of particles and then apply all the forces, right? -and them pass this to the higher version.
I don't see any other way

My plane is 288 by 512 in generic units.
The image size is 1152 by 2048.
Cheers

Ok, when I create a plane with those dimensions and set the the Spacing to 0.5, I get 877,775 particles. Multiply that by 20 and you get 17,555,500 or 17.5 Million particles. This requires around 500 MB to render in Krakatoa, unfortunately passing it through Particle Flow will change that since PFlow has quite different (and higher) memory requirements.

You should use the 877,775 particles (1 random in cube) to produce a PRT file sequence and get the right look in PFlow. In fact, you can reduce the Render % in the PRT Loader, set it to Load Every Nth and the PFlow will use only a fraction of the particles. Get the right motion that way.

Once you feel the particle animation is what you want, increase the particle count in the PRT Volume, save a new sequence, load it into the PRT Loader, change the Render % to 100.0 and let PFlow crunch through the millions of particles (this will take a while). If you have enough disk space, dump the PFlow particles to a PRT sequence so you can later re-render any frame without waiting for PFlow to calculate.

VTeixeira
06-04-2010, 05:19 PM
Now I get it.
In the rendering section the option was in "Load First N Particles". I've changed that.
I've placed the viewport render % to 0,005 and now I can see all the particles still when I mess around the viewport it slows down a bit. My particle count is 17,769,684. I think this is too much. Basically what you recommend is for me to reduce the Rendering percentage and perhaps the % of render also. I'm sorry for being so slow in understanding this but there are some process that I can understand because this isn't Maya but still I'm getting used to this.

After all the forces applied I'll save all the action for me to render it without having to worry with PFlow.
I have a lot of disc space hope my 8 Gigas of Ram don't let me down.
A huge thanks for all this step by step help.
I'll try to post my results as soon as I can.
Cheers

Bobo
06-04-2010, 06:33 PM
Now I get it.
In the rendering section the option was in "Load First N Particles". I've changed that.
I've placed the viewport render % to 0,005 and now I can see all the particles still when I mess around the viewport it slows down a bit.

When the PRT Loader is set to Load Every Nth, it is generally slower because it has to read ALL particles from disk (the PRT file is zipped so it cannot just jump through it, it has to unzip it all), while First N loads only a portion of the file. But because the particles from a PRT Volume are ordered from bottom to top, you would get only a fraction of the plane and not the whole thing.

That's why I proposed to create a very small (less than 1MP) PRT sequence to play with AND set it to Every Nth in the PRT Loader which is then respected by the Particle Flow (assuming you created the ID channel as explained in the tutorial). Particle Flow grabs the particles from the top of the modifier stack of the PRT Loader and respects the PRT Loader's render percentage settings, so if you have 877K particles in the file and load 10% in the PRT Loader, the PFlow should also load and show only 87K particles which should be relatively fast to mess with.

Once you like the forces, you switch to a high-count particle file sequence with many millions and go drink coffee (or red wine, being in Portugal ;)) and wait for PFlow to process the final version. Instead of just rendering, you can switch Krakatoa to "Save Particles To File Sequence" once again and dump all the force-influenced particles, their Velocities, Colors, Density etc. to a new PRT sequence. This will allow you to load the resulting simulation in a PRT Loader and apply post-processing of any channels via KCMs, play with the Density multiplier, tweak the Motion Blur settings, reduce the particle count if needed, cull portions of the particles, even DEFORM the particles with deformation modifiers etc. and it should take a couple of seconds to load and render ANY frame because PRTs are history-independent snapshots of the particles (you can jump to frame 100 without pre-calulating 99 frames each time).

VTeixeira
06-04-2010, 06:46 PM
Once you like the forces, you switch to a high-count particle file sequence with many millions and go drink coffee (or red wine, being in Portugal )
Vinho do Porto :D

This is my test image, I've decided to do a low res version.
I'm starting to render it, to see how the animation behaves.
I like self illumination but I can still use lights to do the job, right?
I'm using 0,5 in the Final Pass Density and in the exponent the value 0.
Perhaps when I increase the particle number I'll be able to play a little bit more with these settings.
Cheers

I've increased the resolution in the rendering section. With 640*480 I've got this pic, but with 2048*1152 the image has a lot of dots. Why is that? How could you maintain that correct look in the teapot? Is it because I don't have enough particles?
Sorry for so many questions Bobo

Bobo
06-04-2010, 08:18 PM
Vinho do Porto :D

This is my test image, I've decided to do a low res version.
I'm starting to render it, to see how the animation behaves.
I like self illumination but I can still use lights to do the job, right?
I'm using 0,5 in the Final Pass Density and in the exponent the value 0.
Perhaps when I increase the particle number I'll be able to play a little bit more with these settings.
Cheers

I've increased the resolution in the rendering section. With 640*480 I've got this pic, but with 2048*1152 the image has a lot of dots. Why is that? How could you maintain that correct look in the teapot? Is it because I don't have enough particles?
Sorry for so many questions Bobo

Yes.

Krakatoa, when rendering in Particle mode, draws each particle as a pixel-sized dot (when the filtering is set to Bi-Linear or Bi-Cubic, it actually covers partially up to 4 pixels in a square (2x2), with Nearest filtering filling exactly one pixel. So if the resolution increases, you will need to provide more particles to cover the whole image. Alternatively, you can render at half the image resolution and resize up in post which will of course result in more blurring.

The other alternative is to render as Voxels. Voxels have a fixed world units size and if there is one particle in each voxel, there will be no gaps between the voxels. The particles that fall into a voxel will all determine what the data in the voxel will be (incl. averaged color, density, velocity etc.). If the voxel size is selected to be close to the pixel size of your final rendering, the results will look very similar to particle rendering (just a lot slower). If you select the voxel size to be several pixels on screen, the resulting rendering will look too pixelated. The Filter Radius can be used to smooth that out, but the result will be blurry.

You can see this page for some examples and discussion of how Voxel rendering works and how it differs from Particle rendering:
http://software.primefocusworld.com/software/support/krakatoa/voxel_rendering_mode.php

So you can either generate even more particles to cover enough pixels as you increase resolution, or render a lower resolution with the current particle count and resize in post, or use voxels. It is the nature of the renderer and you have to tweak the settings to get the look you want - in some movie shots we had used up to 1 billion particles (usually in several passes) to get the look we wanted!

If you have self-illumination (Emission) turned on, the dynamic lighting can be calculated, but it might not appear very pronounced. You will have to play with it to see if it looks good.

Btw, the result looks very promising, esp. taking into account it is mapped on a flat plane... Good job!

VTeixeira
06-05-2010, 04:59 AM
Hello Bobo,
I've been testing my animation but at the moment theres something that bothers me it's a certain pattern that the particles create when they are dissolving. I thinks we can see it in the pic above.
How can I fight that? With more or different values in the force warps?
Probably the increase in the number of particles will also help.
Cheers

Bobo
06-05-2010, 06:00 AM
Hello Bobo,
I've been testing my animation but at the moment theres something that bothers me it's a certain pattern that the particles create when they are dissolving. I thinks we can see it in the pic above.
How can I fight that? With more or different values in the force warps?
Probably the increase in the number of particles will also help.
Cheers

Nope, particle count just makes the effect even more pronounced.
It is completely dependent on the forces you are applying. What you are getting looks a lot like a very strong turbulent wind (but I could be wrong). Possible tweaks include the overlaying of multiple forces with different values and the addition of a Drag force to slow down the motion of the particles on one or two of the 3 axes to reduce the curvature of the waves you are getting.

But this does not even require the current setup for testing - just use a simple PFlow and play with the same forces to see how they affect a fast particle system as you tweak their values. Once you get a feeling of how the various values change the outcome, apply that knowledge to the real scene. It will be much faster to learn that way.

VTeixeira
06-05-2010, 01:04 PM
Couldn't make it without it Bobo.
I'm really loving PFlow and Krakatoa, especially Krakatoa.
It as been an huge learning experience.
I've learned a lot.
I'll post my results as soon as I can.
Cheers

VTeixeira
06-07-2010, 03:57 AM
Hello Bobo,
I've been testing around quite a bit.
One of the things that keeps bothering me it's that xxx pattern.
I would like to change that. What type of forces do you recommend me to use?
Should I keep the wind and work on different settings?


Theres a specific effect I would like to create. I want to maintain that back part of the hair, of the image of the girl above, to keep dissolving. how can I do that? Do I need to maintain the deflector before the end of her hair?


Hope you don't take me wrong with these new questions.
Thanks

Bobo
06-07-2010, 04:51 PM
This falls into general PFlow use and since it is not Krakatoa-related, I will let others comment on best practices.

As I said already in this thread, grab a simple particle system (the default teapot example from the Krakatoa intro will do) and layer multiple Wind forces with different scales and strengths plus Drag forces to slow down the particles to prevent them from accelerating too much. Get a feeling of how forces work in PFlow. Then apply the knowledge to the actual scene. There are free 3rd party plugins like Grant Adam's "BetterWind" that might provide more control, and you could use FumeFX simulations to get more physically-correct effects (in fact I assumed that was what you were doing to start with).

I am trying to provide Krakatoa support here, not PFlow, and I hope you won't misunderstand that either. ;)

VTeixeira
06-07-2010, 05:35 PM
Yes that's right.
Sorry for the questions Bobo.
I'm already doing what you told me before.
If I have any more questions related with Krakatoa I'll post them right here.
Thanks for everything.
Really appreciate all the help.
I'll post my tests soon.

VTeixeira
06-18-2010, 08:58 PM
Hello Bobo,
I've been testing and testing several movements of the particles.
Yesterday I pass it to high res. From 1 in random in cube to 10.
It took me almost one hour to render one frame but it was my surprise when I came to see that The difference between high & low res isn't that significant.
I can only assume it's because of the lack of depth?

JohnnyRandom
06-23-2010, 09:37 PM
Hey Vitor that looks pretty cool :)

VTeixeira
06-24-2010, 06:48 AM
Thanks, really appreciate.
Cheers

VTeixeira
07-23-2010, 02:42 AM
Hello Bobo,
I have just a doubt for you.
I'm testing agian this Dissolve Fx and dedided to do waht you told me here:
Instead of just rendering, you can switch Krakatoa to "Save Particles To File Sequence" once again and dump all the force-influenced particles, their Velocities, Colors, Density etc. to a new PRT sequence. This will allow you to load the resulting simulation in a PRT Loader and apply post-processing of any channels via KCMs, play with the Density multiplier, tweak the Motion Blur settings, reduce the particle count if needed, cull portions of the particles, even DEFORM the particles with deformation modifiers etc. and it should take a couple of seconds to load and render ANY frame because PRTs are history-independent snapshots of the particles (you can jump to frame 100 without pre-calulating 99 frames each time).
Don't I still need to do this:
Since there is no lighting in the scene and we want the particles to appear self-illuminated, Turn on ">Use Emission" in the "Main Controls" rollout of Krakatoa; In the "Global Render Values" rollout, click the Create New Global Override Set - a new helper object will be created in the scene and a Krakatoa Channels Modifier will be added to it automatically.
I'm asking cause I try to do this and got some strange results.
Cheers

Bobo
07-23-2010, 08:26 AM
Hello Bobo,
I have just a doubt for you.
I'm testing agian this Dissolve Fx and dedided to do waht you told me here:

Don't I still need to do this:

I'm asking cause I try to do this and got some strange results.
Cheers

Define "strange" :)

You will be able to override the Emission later at any time.
The saving to PRT simply bakes most of the time consuming portion of the PFlow system and trades off time for disk space. It will eat up a lot of disk, but will let you iterate faster.
Of course, you can save the Emission channel and then the self-illumination will also become part of the baked particles.

VTeixeira
07-23-2010, 02:10 PM
STRANGE because some parts of the particles were gone.
I've decided to add the Emission and MXSFloat to the save channels.
I think this is the correct thing to do, right BoBo?

VTeixeira
07-23-2010, 03:20 PM
An render example:
Why is this happening.
What I'm doing wrong? Do I need to had anything extra?
Cheers


I'll recreate the process to see whats wrong...

VTeixeira
07-23-2010, 07:16 PM
I'm feeling very embarrassed at the moment and quite stupid.
The problem was related with the camera.
I didn't created any so I was using the top view.
I was going crazy trying to find the solution for this and then I rendered from the perspective view and everything turned to be alright.

I did what you told me too Bobo and activated the use emission.
Now I'll had some effects.
I'll post my results.
Thanks

Bobo
07-23-2010, 07:50 PM
I'm feeling very embarrassed at the moment and quite stupid.
The problem was related with the camera.
I didn't created any so I was using the top view.


Don't feel stupid, Krakatoa has some limitations when it comes to clipping planes of ortho views.
We don't recommend rendering from non-perspective views, but it is not very obvious from the documentation (not that anyone reads it ;))

Btw, good job on the thesis, I skimmed over the surface (mostly looking at the illustrations).
Congratulations on the Master degree!

VTeixeira
07-23-2010, 07:54 PM
I usually print all the Help of the softwares I use.
I'm also reading Krakatoa, probably miss that part but It's really true.
I always read the help.

Thank you about the Master Thesis, I've lost my appendix don't know where they are, it will take some time again to put them online.
The Master Thesis is more a reunion of information, related with Fluid simulation.
I think I did a good job in recollecting the basic information for anyone to understand how to create a simulation.

Now it's time to work and finish the showreel.
My next step is to start learning python.,
I have to learn how to program.

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