At the moment I'm just trying to migrate an existing project to 20.5 and I'm getting tons of segmentation faults trying to sublayer or reference USD assets that were fine in 20.

I'm not sure if this is an intentional design choice, but it seems like the Vulkan viewport draws bounding boxes as geometry in shaded modes. It can potentially tank performance and negate the point of having a bounding box representation.

Aside from reverting to OpenGL, is there a way to change this behavior?

brians
Yes eventually, but at the moment we have higher priorities

Sounds good, thank you.

LukeP
4) Quite annoying and haven’t figured this out yet, but say I have a sim… 10 nodes and display / render flag set on the last one. I just want to see parameters of say the 5th node… so I click the 5th node… what happens now is one of the most annoying things about houdini

(a) the viewport starts showing me overlay of the output of the selected node (the same pain point when modeling) what if I don’t want that? I just wanted to see the parameters ffs. Maybe even if I change them, I don’t want to see the geo of the node that I just clicked… I have the render / display flag set on the last node… In some cases I can press escape to disable that, but it’s still annoying

(b) and then of course the nemesis… I just wanted to see the parameters, but because of (a) above, the sim starts cooking.. then I’m left there trying to hammer on the Esc key with no result… maybe after 10s… this in my opinion, if addressed would be a huge list to UX

Hi Luke, have you tried this option? You will need to restart your Houdini session. There are pros and cons to each setting, but for working with cook-heavy networks the "Show Display Operator" mode is nice.

I'm a big fan of houdini-course.com for getting people up to speed, and I've learned a lot myself from Christian.

brians

happybabywzy
but the transmission scatter color not support yet?

No, because that would make it a volume.
The current workaround is to duplicate the geometry and make it a uniform volume.

Hi Brian, are there plans to eventually support scatter?

Hi Dan, for this you would want to use the Render Geometry Settings LOP and disable shadow casting under Shading > Render Visibility.

How are you treating the instances on the Component Geometry node? If you look under the Primitives section, the default is for Packed Primitives to 'Create Native Instances'. Try changing that to 'Create Point Instancer".

It might be less guesswork if you upload an example file.

Native instances are more for situations where you want to be able to manually transform individual instances. For scattering lots of leaves or trees it's better to use point instancers. Attached is an example, please excuse the crappy trees.

No problem. And it's Shift+H after you have an enclosed selection, super handy.

The pages should be topologically consistent, so if you do your face selections inside of a for-loop and create the attribute there, it should be valid for all pages.

dhuiting
Thank you both so much!

I got it working. Scene is not finished but you get the idea...

Now I just need to learn Substance painter and get some texture on the pages and create the book cover

thanks,
Dan

Right on Dan. As far as your other question, you can do two-sided materials in a Karma Material Builder using the Karma Ray Import VOP and setting the Variable Name to ray:backface. The output can then be used in a MtlX Mix node to mix between two inputs, including materials.
Though it does look like the pages have thickness? Looks like there are some normals issues with the edges too.

The Component Geometry, SOP Import, and Scene Import LOPs have a parameter called Partition Attributes. If you set the class primvar there, it should give you a USD GeomSubset per page under the mesh prim. You can assign different materials to those GeomSubsets.

You can find the option under Edit > Preferences > Objects and Geometry > Secure Selection On by Default

From my understanding of it, there are a couple of ways that applications and renderers can support MaterialX: .mtlx documents and/or through USD.

From the Houdini docs: "Solaris and Karma utilze MaterialX through UsdMaterialX". Unless you go through the process of exporting and hand-editing .mtlx documents out of VOPs, MaterialX out of Houdini ends up as UsdShade networks. I think in order for other apps/renderers to faithfully recreate complex MaterialX mats from Houdini they would need to have solid USDMaterialX support. I can't speak to Omniverse or Unreal, but from my testing there are a lot of things that don't work right in the latest versions of Renderman and V-Ray. Maybe Arnold does a better job?

At the moment I get the impression that when you hear this or that application has MaterialX support, it's really more in the limited context of textures feeding into Standard Surface. Most of the .mtlx files floating around out there seem to fit that mold.

As far as out-of-spec nodes, Karma subnets have some goodies that will only work for Karma, whereas MaterialX subnets should only allow you to tab in nodes that are part of the spec I believe.


Happy to be corrected if any of that is wonky.

Instead of splitting the mesh into different prims you could use your groups to set up Geometry Subsets. That way you maintain a continuous mesh, but have separate prims underneath to apply materials to.

tamte

tbay312
if you want to have real fun though, load your scene in Omniverse, turn on iRay's Caustic Sampler and watch your detailed caustics appear almost real time, it feels like magic

That sounds lovely. Can we get that SideFX?
Meanwhile the caustics at home. 10,000 samples with XPU and optix denoiser. I'll have to try CPU with path guiding.




Btw Tyler, if you are doing any sort of comparisons with refractive surfaces, one thing to watch out for is the Enable Internal Reflections setting in H20: https://www.sidefx.com/forum/topic/93357/ [www.sidefx.com]

That reminds me of an RFE I submitted in late 2022...

Hello SideFX team, it would be great to see faster manipulation of assets brought in via the Stage Manager LOP. What I would like to do: Bring in a model, place it, bring in another model, place it and make adjustments to both, place another model, make further tweaks to all three, bring in some more etc etc. The issue is that the Stage Manager LOP doesn't let you select a different prim in the viewport without first explicitly hitting the 'S' selection shortcut, and then Enter to bring the transform handle back up. This results in extra clicks when making layout adjustments and slows down workflow. If you select prims in the SGT, the transform handle automatically switches to the newly selected prim, or you can click the handle gizmo icon in the Stage Manager's QT panel. Neither of these are fast selection methods and I would consider it bad UX for doing quick layout edits. We also don't seem to have the ability to manipulate more than one prim at a time, which is another workflow killer when populating a scene with the Stage Manager. The Edit LOP handles these sort of quick edits much better, it would be nice if the Stage Manger could match that behavior. Thank you.

Thanks everyone, "Enable Internal Reflection" did the trick! I was not aware of that parameter in H20.
I'd agree that it should be enabled by default. Too easy to miss, and the differences in the look are massive.

Thanks for the suggestion jsmack. There is no visual difference when unclamping the color limit in this scene.