Hi Folks,

I have been working my way through learning Houdini using the Indie version that I purchased (13.0.509) so advance apologies if the terminology and/or descriptions below are difficult to follow.

I've run into an issue that I can't seem to wrap my head around and wonder if someone on the forums could provide some guidance. I have a simulation sequence - shattering columns - that I ROP'ed out to BGEO and am reading it back in. I created 4 GROUP names (left, right, front, back) when initially building the columns in anticipation that I would need these groups to specify materials.

At the scene level, I created a Geometry object and inside the Geometry object is the Read Geometry file node. I can successfully read and playback the simulation. I have added a single ENVLIGHT set to INTENSITY=2.

I'm now looking to apply 4 separate materials (.JPG files) to the columns, one material for each side, at different UV scales. I created 4 SHOP materials pointing to the respective .JPG's and tested each on a simple cube … all good.

Problems I'm having, which makes me suspect I'm missing a few workflow steps:

#1 - If I add a UVTEXTURE node (GROUP=front, TEXTURE=Face, SCALE=.1/.1/.1) followed by a MATERIAL node (GROUP=front, MATERIAL=/shop/frontmat) I can see it fine in the Viewport.

When I render however, it renders black.

Changing the texture type value allows it to render but the scale/offset/angle seems to get ignored.

#2 - I can see the cracks where the simulation will occur during Frame 1 render.

Not certain why they are visible as the breaking begins several frames later … almost as if it's rendering wireframe + shaded.

#3 - Adding additional UVTEXTURE and MATERIAL nodes for the other sides (groups) and attempting to merge the results yield black renders regardless of settings.


I tried applying UVTEXTURE and MATERIALS pre-simulation (i.e. as part of column creation)… doesn't seem to make a difference.

What is the proper workflow to use when looking to assign various materials to different parts of a simulation read in via Geometry Read?

Advance thanks,

hgagne

Well, managed some progress …

On #1:

It seems like the simulation returned from the DOP is indeed entirely new geometry. I suppose this makes sense and although I've scoured the documentation a few time over now, I didn't spot any info supporting this assumption.

What this means is that all UV Texturing pre-simulation is pointless since it's all destroyed during the simulation.

On #2:

I used the UVTEXTURE and MATERIAL nodes post my DOP IMPORT nodes, right after the EDGE CUSP nodes. I merged all of the simulation parts (6 in all) and ROP'ed the merged results.

Effectively, I've UV Textured each part of the simulation and applied a material to each part using the groups I had created. This seems to allow the retrieved BGEO to display with texture in the Viewport.

I'm not entirely sure as to why, perhaps it's a result of how I built the simulation.

On #3:

Had to reconstruct the MANTRA materials from scratch and reassign the texture .JPG files to each MANTRA material.

Afterwards, I was able to add a MATERIAL node after the FILE READ node that retrieves the ROP'ed BGEO. I added 4 materials and set each material tab to point to the respective MANTRA material (front, back, left, right).

It now renders as expected and it also overrides the “built-in” versions of the materials (tested that with some dummy .JPG's) that I ROP'ed out as noted above.

Again, not entirely certain as to what is going on but I'll assume it's my approach and/or newness to Houdini.


On a separate note, although there's all kinds of documentation/videos on the Side FX site. Most of it is out-dated. Seems like Side FX needs to allocate additional budget dollars to increase the documentation and training teams.

Lots and lots and lots of gaps … making the learning curve on this product unnecessarily steep.

Regards,