Procedural Generation Of A Point Cache For Vfx Graph

I have some simulation data which results in 100,000s of positions and colours which is exactly what the morphing face demo from the VFX samples uses from the point cache. The graph doesn't necessarily need the point cache itself just the attribute maps for position and colour which I have arrays for in C#.

It looks like the attribute maps themselves in the graph are designed to take a texture 2D but when I pass in random textures instead of the positions from the point cache the results look nothing like the images. What type of image do I need to pass in to be able to control the positions and colours of the resulting graph?

Ideally I can just reference the visual effect component, pass in 2 textures that I generate in runtime and then get my expected output rendered.

 

Hi Remy, this is great and it's good to know I was heading in the right direction. I just want to clear up a couple of things though:

So the texture's rgb values need to represent the xyz values of my position array and the alpha channel is supposed to contain my color index but what actually is that? Is the index supposed to just be integers increasing from zero or will I need to assign more specific values to align my positions texture to my colors texture?

I assume the colors texture will simply contain the rgb values I want but does the alpha channel represent anything special when it comes to a color attribute map like with the position? Or just normal transparency?

Finally, the float values stored within my position texture, do they need to be normalized between zero and one like with colors or can I store the true world space positions that I want in the texture?

 

Oh an one last thing, your screenshot cuts off before the sample texture 2d node feeds into your main graph. What block are your final s and w properties feeding into?

 

Bumping this thread. I know procedural point cloud rendering with millions of particles is exactly what's needed in engineering fields and I'm sure many more people besides myself could benefit from learning how to do this but I don't quite understand the full picture.

 

Perhaps some of the code in the following might help you understand better?

https://github.com/keijiro/Smrvfx

edit - or some parts of this one (since one of its features is to store imported point clouds into VFX attribute map textures):

https://github.com/keijiro/Pcx

 

Hello,
any news about how to use the output of the graph above? Where do I have to plug in s and w?
Thanks a lot

 

This post is a little old right now, but I managed to find out some time ago how Remy's node setup is supposed to be used.
I created a video on how to combine 2 point caches and interpolate between them to demonstrate that:

To briefly answer an issue I think most people have with Remy's screenshot:
The texture put in the SampleTexture2D node is the attribute map of the point cache and the data width and height equal the square root of the point count, because you can see a point cache kind of like a square texture.

If you want to know more about the details, I encourage you to watch the video, as it is a little difficult to explain without example content.

 

I've had some success getting a switchable number generator in the VFX graph. I have had some trouble, however, getting the effect to work cleanly. The point caches create really clean numbers, but using the setup from above (thank you SO much for that work, by the way) produces some odd results. Any idea how to clean this up a bit more? Some numbers are worse than others.

 

So can I create point clouds at runtime and control them with compute shaders?

 

Very useful video + example @narranoid! One wrinkle: I'm trying to use your approach, and it works well with an un-decimated point cache (one with full dimensions, ie. 1024 x 1024 or something) but not with a decimated point cache (one that gets rid of transparent pixels). SetPositionFromMap handles this case fine. Do you have an idea of how one might extend the example to work with such a pCache?