Maya to Houdini and back again - Textures and destruction workflow?

[cwalrus]

Hi guys - 

 

I have a model that's textured in Maya. I want to take it into Houdini, blow it to pieces, and then send it back into Maya for the final rendering, ideally with the textures I assigned primarily. 

 

Is this even possible, and if so what's the workflow? 

 

I tried it with an Alembic from Maya to Houdini and back again, but when the object shatters, Maya thinks its a brand new object and drops the textures. Then I selected all the debris and re-applied one texture - while that works, the problem is that some debris is from objects with different materials... e.g. a chunk of window with its frame and the wall would be three different textures.

 

THANK YOU!

[fathom]

the problem is your fracturing step in houdini.  i would suggest fracturing in houdini, then going back to maya to assign textures/materials on the new fractured geo.  then back to houdini to run the sim and use your sim to position your packed geo from maya (2nd export).   ideally that will keep everything intact and you could then export that as an alembic and it'll be happy in maya.

 

you might also consider exploring alembic references -- that might make resims and imports a bit easier to handle non-destructively.

[anthonymcgrath]

how does this work with a skinned character?  eg i have a fully rigged and animated character in maya.. i want to export it to houdini, run a deltamush on it and some other bits for skin jiggle etc then bring that back to maya for rendering.  my shaders are assigned to various polygon face groups so the body/legs/arms have one shader with textures and the head has another similar setup.  are there ways to tackle this ?

 

thanks!

ant

[Neon Junkyard]

The way I usually handle this situation is to separate all the UVs per material into their own UV tiles. Say you have an object to shatter that has existing UVs. you keep all the original UVs in the 0,0 uv tile, then create UVs for the inside shattered pieces and translate all those UVs over to their own UV shell.  Do that for each material on the object, just make sure all the UV shells per material are in their own tile.  When you export alembic back to maya make sure you are exporting the UVs as a vertex attribute. Here is a really great tutorial from toadstorm on seamless maya <> houdini workflow -  http://www.toadstorm.com/blog/?p=435

Then to set up multi-tile UVs in maya without having to use the UDIM preset on the file node, you basically daisy chain all your textures together into the default color slot of the previous texture starting with the 0,0 uv tile. Then in each place2dtexture node uncheck wrap u and wrap v, then under translate frame, translate it over to its corresponding UV tile in the same way you did in houdini.  so first texture is 0,0  second is 1,0  third 2,0  etc

You can use the same trick to separate out materials too, depending on the renderer you are using. For vray you would just make black and white masks in the same way and pipe them into the mask input of a vray blend node for instance.  

This is also a good way to get around all the issues associated with face assignments in maya.  I attached really simple examples for each of these.  In the maya file I used ramps to avoid external file dependencies but you could just as easily substitute those for file nodes

 

 

multiTile_uv_fracture.hipnc

maya_multiTile_uvs.mb

Edited August 16, 2016 by Neon Junkyard

[cwalrus]

thank you