Houdini fixed Point Count

[Max Schwugier]

Hi everyone, 

 

I am doing Houdini now for over 2 years and I love the software and the community! I recently face a big problem which i cannot solve on my own and cant find anything out there. to understand my problem you need to understand my workflow: 

since i got a redshift liceense locked with c4d i cannot render inside of houdini :/ so i usually create the simulation inside of Houdini and export it to c4d via alembic to render it there with redshift. (which is allready enough pain) 

 

whenever i create a particle simulation which has no constant point count like there are spawning new ones or they are dying somehwere i get really weird results in c4d with the cloner or rs matrix. 

 

i copy single polygons to the points in houdini and export it via alembic. In c4d I scatter now custom objects like different stones (stone A, stone B, stone C....) on the polygons and set distribution to polygon center so every single stone gets the same position as its particle. Or in other words: every polygon receives one particular stone. I also activate scaling from source so for example if i use grains with different size the scattered stones in c4d also get the same size and pretty accurate collitions. if now a new particle gets spawned or dies Stone A becomes stones B on the same location. this results in flickering evertime a particles spawns or dies.

I also cannot use a random effector to drive the rotation or color of each stone because it changes every frame. 

I managed to find a workaround: I just keep the particle count the same without spawning or dying particles but i scale them to 0 or 1 but this is no real solution for me. Since i need to create a lager simulation and just pick out a small piece which i then need. So here is my questions: 

 

1. Is this a Houdini Problem or is it a c4d Problem? 

2. how can i fix it?

3. if it cant be fixed are there better workarounds?

 

If you need a video or scene file or something from this problem let me know ill upload one but its for a client job and i cannot show too much. hope you understand and thanks in advance! 

[Ziyad]

Hey Max, 

I would suggest instead of doing the copying of polygons inside Houdini you can just export the particles as an alembic, then inside C4D you'd have to import them as "particle geometry" to allow redshift to read them as particles inside the redshift object tag. After that you can choose any method you want in rendering these particles (e.g. custom objects, which allows you to drag the custom stones you have to be scattered on the particles).

[flcc]

When you import "as particle geometry" internally C4d use Thinking particles wich is cumbersome.
Effectively when importing particles, even with a constant particle count particle id change over time. this is a thinking particle related problem.  i've been having a pretty hard time wrapping my head around this problem.
But if I understand correctly you want to use the particles as as scatter source. Why export a sequence ?
For this kind of workflow I prefer to import the particles "as polygon Object".
The imported object has no polygons, but points are here.
It's really easy  to use mograph stuff with that.

 

Edited December 9, 2021 by flcc

[Max Schwugier]

@Ziyadwhat i hate about thinking particles: you cannot translate it in c4d. you cannot change the position nor the size or rotation and as @flccsaid it does not solve the problem i think because the particle id still changes. 

But thank you very much @flccgotta check that out