Houdini 21 (Hydra Scene Index mode): native Houdini primitive geometry does not render in hdMoonray

Open
  • Is something wrong?
#245 4 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
44/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
cmake, cpp
Domain
computer-graphics

Research direction

The report identifies Houdini 21 Hydra Scene Index handling of native primitives as the failure area, but gives no source file or test path. Start by locating the Scene Index primitive handling and reproducing with a Sphere LOP in Houdini 21; compare against the working USD asset and Houdini GL results. Done means native primitives render in Moonray in Scene Index mode.

Written by the indexing model from the issue text.

Description

Under Houdini 21, Hydra runs in Scene Index mode, and hdMoonray doesn't render native Houdini primitives. A Sphere LOP renders blank with Moonray, but renders fine in Houdini GL, and a USD asset (crag) renders fine with Moonray. So the geometry is valid and the delegate works; only native primitives in Scene Index mode fail.

Env: macOS Apple Silicon, Houdini 21.0.631, Houdini USD 23.x (v0_25_5), Python 3.11, hdMoonray 6.41.0.0, scalar exec mode.

Repro:

  1. Sphere LOP in Solaris, render with Moonray → blank.
  2. Same sphere, Houdini GL → renders.
  3. crag.usd with Moonray (Debug) → renders.

Sphere + Moonray (blank):
Image

Sphere + Houdini GL (renders):
Image

crag.usd + Moonray Debug (renders):
Image

Rob Wilson confirmed on ASWF Slack this is a known Scene Index limitation he's working on:

if you are using Houdini 21, it is running Hydra in SceneIndex mode. There are few things that don't work in that mode, including primitive geometry. I'm currently working on fixes for these issues.

Slack thread: https://academysoftwarefdn.slack.com/archives/C0AHKA6E17Z/p1776195285395069

I have a working Houdini 21 / macOS build and am happy to help fix this — pointers on where Scene Index primitive handling lives would be welcome.

Dominant language
CMake
Stars
4.7k
Forks
321
Avg merge
13m
Merged PRs (30d)
3

Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from OpenMoonRay/openmoonray

All issues in OpenMoonRay/openmoonray

Similar issues

More Computer Graphics issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.