uv mapping colors to a ball of sand

[sulkybunny]

Hello experts of the world..

I am a gig that needs to have an apple made out of sand..  so I would need to color map my real mesh apple maps onto the sand..  

any ideas? I am new to the graph...  I can manage making the actual sand starting from apple shape and breaking down , that's easy, but shading it to look the apple .. I am clueless 

thanks 

[Christoph_Schaedl]

Thats a good question. It could work if you bake the color onto the appels vertex colors and them bake them to the particles.

Or you try todo it with OSL in the Shader.

[sulkybunny]

Thanks cg oglu 

both of your options sound interesting but I am new to bifrost graph... please send some more details?

you are saying there is a node that will pull vertex colour from my apple...  (I would need to convert my texture shader to vertex colour right? And then there would be a way to bake those onto the sand particles..  ?

and what’s OSL? 

sorry for cluelessness..  but I am a fast learner! 

s

[Christoph_Schaedl]

Here is a thread that could help. 

https://forums.autodesk.com/t5/bifrost-forum/point-color-from-image/td-p/8928472

And OSL is a shading language. It could help to create the shader for the sand. Arnold does support OSL. 

https://github.com/imageworks/OpenShadingLanguage/

[JMM71]

Hi

I made a video a while ago showing how you can bake  vertex colours onto mpm.

Should help you get started.

I made it in a previous version of bifrost so some of the connections may have changed or may not have, I haven't checked, but the work flow will be the same.

https://www.youtube.com/watch?v=4ch3Tmvpl44&t=2s

Hope it helps

[sulkybunny]

thank you Plastic Egg 

this is exactly what I was looking for..  

super simple solution .!

[sulkybunny]

Hey JMM7

thanks for the solution... 

did you run into any issues with getting the mpm snow to render subsurface with Arnold? for some reason when I dial it up the particles go black.. my color is working fine with the Aiusercolor node... 

and weirdly, when I change my particle type to cube in the mpm settings, subsurface works.. its the spheres and all the other types that turn black?  any ideas?

thanks 🙂

[JMM71]

Hi

I just tried it and have the same problem, might be a bug.

If it is a bug, you can do a work around where you instance spheres onto the mpm and apply the shader to the instances. I tried it and it works(ive attached a simple scene showing the workflow). If thats not suitable for your project, then I think its a question for the bifrost team.

J

[sulkybunny]

Thanks J

ill try that 

Do u have a website / email for business contact? 

saul 

[sulkybunny]

Hello again clever people 

ball of sand is nice... how ever I am struggling with getting it to do exactly what I want.. :).  I managed to make it fall apart like dry sand ,, and I managed to break it up into three or four big chunks (firmness way up)

how would u go about making it crumble like a rock face? Imagine a ball being tapped from the top and then breaking apart slowly..  ? Any ideas?  I tried using vary node on different properties but really doing it?   Is there a way to control the clumping of it?   

would love any ideas,, thanks 

[mihirsbcc]

I followed the video. I also baked the texture. While painting vertex color mine do not flood to white but I imported the map and I saw it in editor and changed it to color. My problem is at frame 33 I am not seeing bifrost object. The graph is fine. any help is appreciated.