Thinking Particles


#1401

No problem…glad I could help. Regarding exporting, I usually just render the cached TP system to avoid adding extra steps to the pipeline.

Exporting can be useful if you need an easy way to re-time sims, if you need to use certain plugins with your geometry that dont play well with tp, or if you are sending sims to a client.


#1402

Hello everybody!

I need to compute velocity and alignment from a previous position and the current one. Every frame my particles get repositionned on the surface of an object. I can extract with the memory node the previous position but I don’t know and understand how the math work to extracte alignment… I need the particles to align with the motion of the objects. If someone can help me with this…

Thank you in advance!

Maybe I should use Surface follow operator… I also have doubt about motion blur and this technic.


#1403

You can use Position/Position + dt and Alignment/Alignment + dt outputs of the Particle Data helpers.
some small test scene ro more detailed explanation would be better.


#1404

Hello everyone !
is it possible to make particles aligned to the particle object ? I found that I can use the node and surface pos to make the particles borned and attach on the object with the surface alignment, but when I use the obj to particles, e.g, I use some rocks to particles by using “obj to particles” or “geom instance” , and i want to born another particles on the surface of it, i use the input of particles shape in surface pos node connecting to my rock’s group, and port the alignment to the position born though particle data, but the new born particle didn’t align on the surface… I can only parent them to my rocks by using pattach, if they could align with the surface it would be perfect ! please give me some advise and correct me if I am wrong, thanks alot !!


#1405

Hi everyone.

I´m traying to get this effect http://www.youtube.com/watch?v=yKFTgSAdS1U, but I dont have any clue at how to get that cloth like particle deformation.

This is what I get until now. http://www.youtube.com/watch?v=0NoGqhJH5lI

If anyone can give me a clue I will aprreciate it much.

Sorry for my very bad english.


#1406

i think its first precut with something like rayfire, then it use something like spherify modificator, and then its simmed with SC


#1407

try this one:
https://www.dropbox.com/s/f2by5zc653pldlr/born_on_particle_surface.max?v=0swn

screen:
https://www.dropbox.com/s/dqwarplid5qh61f/born_on_particle_surface.JPG?v=0swn


#1408

Hey guys, hoping I can get some advice…

  1. I’ve been experiencing a slight offset occasionally with the fragment node.
    Object to particle and GeomInstance both reference the position of my animated prefragmented mesh correctly but the fragment node seems to offset the unactivated portions position over time.
    I’ve tried adjusting every parameter of the fragment node out of pure desperation, some parameters lessen the offset but nothing seems to completely fix the problem.
  2. Not really TP related but to avoid starting a new topic…
    When using the resulting fragmentation from TP to drive selecting and deleting parts of the original mesh the animation of the object disappearing seems a bit jumpy.
    Wondering if anyone has any pointers on smoothing the transition out a bit better without upping the resolution as what i’m working with is already fairly poly heavy.

This may all seem a bit vague so here’s a link to a clip with the result of what I was attempting.
https://vimeo.com/66700600
Hopefully you see what i’m trying to achieve here.
If any more specific details are needed to help troubleshoot this please let me know.
I’d really like to nail this effect and at this point you guys are probably my only hope.


#1409

Have you tried this technique? http://www.andvfx.com/861/thinking-particles-destruction-deforming-object-tutorial/

If you have the volumebreaker plugin you can prefrag it but keep the smoothing groups in tact even. rest would be as in the tutorial.


#1410

its quite odd, recently i did some “mid poly” VB of animated mesh and didnt get errors like u have,
the setup for this is pretty basic, its
Obj2Part, then activation by light in Fragmenter Node, then activated parts are sent to VB

the hardest part is preparing geometry i think, i did use RayFire Modyficator (working on polygons), i’ve kept all frags in one mesh, then these frags were skin wrappe’d to the original animated mesh, and these skin wrapped mesh was imported as obj2part.

here’s a sample:
https://vimeo.com/66735342


#1411

@Anselm- Very similar to how i’m going about it…
I do use VB for the prefrag but for me recalculating it on every frame is just madness when dealing with lots of fragments on a deforming high poly mesh, slows my machine to a crawl. Also, the fragments are still clearly visible even though the mesh is smooth because of the subsurface scattering in the skin which is more obvious still when a solid material is used on the inside faces.
So, i’ve been caching the skinned fragmented mesh and using the volume select and delete method I mentioned which speeds things up a bit and solves the shader issue.
EDIT- It was recalculating on every frame because it was at the top of the stack. Moved under the skin modifier it only calculates on the first frame. Absent minded… And I was wrong, the mesh still loses it’s smoothing when instanced in TP.

@Tomasz- I did a previous test with a full character and never noticed the offset problem.
Not sure why it shows on the arm by itself.
I thought it may have something to do with the pivot points or some other geometry related specific but I’ve checked. I modeled, rigged and animated the whole thing myself and I was very careful about pivots, transforms, etc.
I’ve kept the frags as one mesh through vb, skin wrapping, cached with xmesh & alembic…
I have no idea what it could be.


#1412

hmm, i recall one such thing when objects were flying away at some point, it was a tp BUG, but can’t remember what exacly it was, i may try to search for it if u want

make sure u don’t use Fragmenter and VB in one dynamic set


#1413

Nah, not flying away… more like shifting, as if it’s using a different pivot point.
I always separate my dynamic sets too as I tend to set cache levels for every event.


#1414

can’t help u without seeing scene files:)


#1415

Wouldn’t you know…
When I try to setup a lighter file to post, I can’t replicate the offset issue.
Anywho…
Thanks a bunch all the same!
(Would still appreciate any tips on deleting the fragmented mesh from the original.)


#1416

it seems you’re using GeoInstance in different dynset where it applies every timestep (and recalculates transform matrices (pivot) in order to compensate changing geo. Apply it only at particle birth or if you have animated geo (fractured and skinwraped for example) then use Obj2Particle instead.


#1417

@3ak… you nailed it.
In my earlier tests I was using GeoInstance but later stopped using it.
It just seemed pointless, I’ll avoid doing that again.

I did notice also when testing with the VB modifier as Anselm suggested, the mesh still has the fractured look once instanced in TP even though it holds it’s smoothing outside of TP. Still trying to find the best way to delete elements from the original mesh to get a smooth render. If there was a way to look up the element that has been activated in TP and delete those elements on a sub object level inside of the VB modifier… Unfortunately, the modifier doesn’t provide direct access to the elements it creates. :sigh:


#1418

sorry, i don’t get it)
if you’re about volumebreaker modifier (not the part of the tp) than it doesn’t have element subobject (only gizmo). do you mean fractured and collapsed object?
and while it’s just object it renders smooth but being imported in tp loose its smooth. groups?

small example file would be good)


#1419

You got it.
That’s exactly what I meant.
I use the VB modifier (not the TP VB) to fragment the object.
It keeps the smoothing groups, I think… or maybe the original object normals, i’m not sure how exactly it does it but the geometry renders smooth outside of TP. After bringing it into TP and rendering it has the obvious prefragged look that i’m trying to work around.


#1420

I figured out how to delete elements from the VB modifier while keeping the smoothing.
Genome provides ways to make selections that either aren’t possible with or work differently than the native Max modifiers, after the selection is made then a delete mesh modifier can be used to remove the elements. As soon as I figure out how to make the selection based on TP groups all will be good.
Something to note is that only the skin modifier keeps the smoothing with this method.
Point caching and skin wrapping do not.
If anyone might know how to help with Genome to select elements by using a specified mesh or TP directly, help would definitely be appreciated.