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ruchitinfushion
06-05-2012, 03:42 PM
It's great info by damian Nenow in siggraph
Autodesk® 3ds Max® with Damian Nenow of Platige Image (http://www.youtube.com/watch?v=LBovH7_um_s)


And here is nice tutorial for 3ds max to create cloud in same way.

Cloud Tutorial (http://www.youtube.com/watch?v=hy_oP6DRPiY)

in same style i want to create clouds in maya but not having idea about tools like TranslucencyMod & VertexColourRenderer,so plz give me some advice.Thanx

ruchitinfushion
06-21-2012, 01:26 PM
Is there any way to bake complete map of mental ray physical sun & sky??

SebKaine
06-21-2012, 01:58 PM
well don' t know how exactly he do this, but basicaly i would
- combine sphere and merge them as a blobby poly object (using Nparticles)
- emit particle from this object and goal them on it with parent uv
- had a soft noise and rotate to get slow movment
- paint 10 nice puffy sprite from cloud photo
- create a directional light to get a vector direction of the light
- create an expression that :
- get the parent UV of each particle
- get the position of those coord on the blobby mesh
- compute dot product beetween my light direction and the normal of the point of the blobby mesh
- use this value as a normalized multipliyer for brightness of my sprite
- The most convenient way would be to use a RGB remap for this as R would be full light G half light and B shadow area
- also add some random opacity PP to multiply the sprite

So you get a puffy sprite Cloud with RGB light info and your color all in comp

hope this helps !

cheers

thematt
06-22-2012, 01:58 PM
nice post Emmanuel! lots of good tip in it! couldn't say better.

Of course he could also use your tool that would give close result too..since you seems hesitant to post it, I'll do it :)

http://forums.cgsociety.org/showthread.php?f=86&t=1027355&highlight=cloud+tool


cheers

ruchitinfushion
06-22-2012, 06:57 PM
@SebKaine (http://forums.cgsociety.org/member.php?u=204721) thanx for reply..will try to follow ur step.thanx

ruchitinfushion
06-24-2012, 07:09 AM
I made model of cloud inside 3dsMax & exported to Maya with vertex color baked.See attachments for Maya scene.
http://i410.photobucket.com/albums/pp186/ruchitinfushion/CloudMesh00015.png?t=1340520281

Now i can emit particles from this model with surface emitter and using
goalU = parentU
goalV = parentV
and i can get cloud shape with particles.
Now @SebKaine can you please elaborate more below part.


-create a directional light to get a vector direction of the light
- create an expression that :
- get the parent UV of each particle
- get the position of those coord on the blobby mesh
- compute dot product beetween my light direction and the normal of the point of the blobby mesh
- use this value as a normalized multipliyer for brightness of my sprite
- The most convenient way would be to use a RGB remap for this as R would be full light G half light and B shadow area
- also add some random opacity PP to multiply the sprite

Thank you


Scene File (https://rapidshare.com/files/583611011/CloudModel.zip)

chafouin
06-24-2012, 10:45 AM
I personally did it without using particles (they don't use particle sprites either as far as I know, you don't want it to always face the camera), but scattering planes on the vertices of my cloud. Then you just need to use the Transfer Attributes to transfer the Vertex Colors and that's it.

The biggest problem with this technique is that you see the cuts where planes collides, and I think there is no way to fix that. The same problem would apply with sprites anyway. Or if someone could tell me if you can make a "geometry fade" (with polygons or sprites), that would be great.
Maybe using an occlusion texture? I tried it but didn't get good results.

SebKaine
06-24-2012, 07:02 PM
Ruchit >
well i did some test to follow the workflow he use. Basically
- he combine polysphere to blobby > can be done in maya
- create auto UV > can be done in maya
- bake some kinda physical sky to texture with v-ray > Can be done in maya if you use v-ray. But i try do it with mental ray by using Vertex Bake or texture bake and both result sucks as i get correct direct illum but i don't get Final Gather Bake(maybe i'm guilty on this one ...:)).
- he transmit texture info to vertex info > could be done in maya i think but you must script this and it could be a potential PITA ...
- Create random plane per vertex and giving them the vertex color > could also be done i think but again script involve and potential PITA again ...

So to answer your question if you use v-ray for baking GI in texture and if you do extensive mel script , this kind of workflow should be possible in maya. But be prepare for some headache !

What i don't like in this workflow is
- your stuck and you must rebake everything if light change
- the final result doesn't look like cloud from the result he show in his tutorial ...
- for the plane that are none oriented to the camera i could be wrong but if a plane is not facing the camera, you get a weird slice and you directly see that its a texture on a plane ??? but maybe i miss something here !

basically i will try to do something like this for sprite base stuff ...
http://ofb.net/~niniane/clouds-jgt.pdf
http://www.3dtotal.com/index_tutorial_detailed.php?id=478&catDisplay=1&roPos=1&page=1#.T-djhrW5m8o

i've made a quick test to light sprite in an RGB way i've attach a file, its really a startup but lot of enhancement must be done to make it work nicely i'm afraid ! :)

Fabien >
How are You dude ? :) Nice to see u here !

ruchitinfushion
06-25-2012, 04:25 PM
@SebKaine
after trying this tutorial (http://www.3dtotal.com/index_tutori...=1#.T-djhrW5m8o (http://www.3dtotal.com/index_tutorial_detailed.php?id=478&catDisplay=1&roPos=1&page=1#.T-djhrW5m8o))
I am quite excited to do test on something realtime & your expression is super cool,with use of that i can do lot's of color correction in comp to get good looking cloud.Below i found some material to do something amazing

Reference:
https://vimeo.com/tekano
https://vimeo.com/30701739#
http://www.youtube.com/watch?v=eq9KpZdp6cA
http://www.youtube.com/watch?v=NgCYz6_fsII&feature=relmfu
http://www.peranders.com/w/index.php?title=Fake_Sub-Surface_Scattering
http://colinbarrebrisebois.com/2011/03/07/gdc-2011-approximating-translucency-for-a-fast-cheap-and-convincing-subsurface-scattering-look/

SebKaine
06-26-2012, 11:05 AM
good links ruchit.

i look again and again to the first video, and Fabien is right he doesn't use facing camera sprite. The thing is that those clouds looks really great but if ou pay attention you can see that when the clouds rotate weird slice problem occur ! we don't care in that case as the result is stylistic clouds, but if you want to go to the photoreal way it will be a problem.

But this kind of bake to map, transfer map info to vertex , read attribute, transfer attribute to object and render attribute is really devise for a procedural workflow i think. You can loose your time to script mel procedure and try to get over all the headache ... or you can choose the tool that will give you what you need to achieve your goal in the fastest way (max, ice, H) ...

just in case you use the expression i give, you will have to remap the lighting by taking account of the Y info. the bottom part in shadow must be darker than the upper one ... You could also use other light in the same way to define the shadow and scatter area ... But again lot of work involve for a result that will never be as good as what you could get in H for ex :)

Mixing Fluid and Sprite is i think the best way to achieve the most realistic look, as fluid will give you depth and nice lighting and sprite will add some photoreal cloud patterns in an easy way !

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