topic Re: uv mapping colors to a ball of sand in Bifrost Forum

uv mapping colors to a ball of sand

sulkybunny — Thu, 21 Jan 2021 15:21:02 GMT

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

Re: uv mapping colors to a ball of sand

Christoph_Schaedl — Fri, 22 Jan 2021 08:54:56 GMT

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.

Re: uv mapping colors to a ball of sand

sulkybunny — Sat, 23 Jan 2021 21:45:02 GMT

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!

Re: uv mapping colors to a ball of sand

Christoph_Schaedl — Sat, 23 Jan 2021 22:24:59 GMT

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/

Re: uv mapping colors to a ball of sand

JMM71 — Sun, 24 Jan 2021 11:43:56 GMT

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

Re: uv mapping colors to a ball of sand

sulkybunny — Sun, 24 Jan 2021 15:03:27 GMT

thank you Plastic Egg

this is exactly what I was looking for..

super simple solution .!

Re: uv mapping colors to a ball of sand

sulkybunny — Wed, 27 Jan 2021 11:02:13 GMT

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 🙂

Re: uv mapping colors to a ball of sand

JMM71 — Wed, 27 Jan 2021 12:57:15 GMT

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.

Re: uv mapping colors to a ball of sand

sulkybunny — Wed, 27 Jan 2021 13:50:49 GMT

Thanks J

ill try that

Do u have a website / email for business contact?

saul

Re: uv mapping colors to a ball of sand

sulkybunny — Sun, 21 Feb 2021 10:19:09 GMT

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

Re: uv mapping colors to a ball of sand

mihirsbcc — Mon, 22 Feb 2021 10:17:38 GMT

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.