3D Object Transparency / VDMX

Steps causing the bug to occur

  1. build image generator scene using multiple 3d Objects. Add a shader with some transparency. Combine those objects and render to image for use in other applications
  2. transparency of all shaders is missing.

Have you found a workaround?

Need to render each object to an image then use blend images to composite scene.

Other notes

  • Vuo version: 1.2.6
  • macOS version: OS X 10.10
  • How severely does this bug affect you? It prevents me from completing a specific task with Vuo.

In previous versions of Vuo. I’ve always combined the scenes using the Combine 3D Objects node. Something about this node feels like it’s been changed.

Blight3.vuo (12.1 KB)

Blight4.vuo (14.8 KB)


I believe the issue lies with VDMX. I was able to get transparent shaders by using an older build of VDMX. Which tells me it’s not an issue on Vuo’s side.  

Upon further investigation, we believe this may be an issue on Vuo’s side. It’s rendering fine in VDMX if you render as a dylib.

Hmm, I’m trying to understand the problem — could you help me out with some more explanation?

If I open Blight3.vuo and Blight4.vuo in Vuo 1.2.6, render them to ProRes4444 movies (with alpha channel), and view each video in a movie player that supports alpha (attached), they appear to have the same alpha characteristics. Same when opening them in VDMX with the Vuo 1.2.6 framework.

Could you point out the difference between the two compositions’ outputs? Or if that’s not the right way to reproduce the problem, could you elaborate on the steps you took?

alpha movie player.vuo (3.53 KB)

Hi Jaymie, the file Blight4 is the workaround. They should both produce the same results in vuo processes. The problem occurs when I run the Blight3 generator in VDMX.

The difference between the two. Is that blight3 uses a combine 3D objects node to layer the objects in the scene. And Blight4 uses Render scene to image node for each 3D object. Then those images are composited using multiple Blend Image nodes.

Are you able to run Blight3 in VDMX without the “run vuo in separate processes” preference enabled?

without the “run vuo in separate processes” preference enabled

Ahh, that’s the key. When the Vuo composition is running in the same process as VDMX, VDMX has to provide a graphics thingy (the OpenGL context) for Vuo to draw on. Vuo is expecting the OpenGL context to be in a certain state, but VDMX is providing one in a different state — understandably, since we hadn’t documented exactly what state it should be in. We’ll take care of this in the next Vuo release.

acknowledged. Looking forward to that fix. I have found that running in separate processing causes some serious trigger lag/freezing. I’ve found that preloading the vdmx media bin and triggering them once before a show puts the comps into ram. then you can trigger them without any noticeable lag/freezes.

As of Vuo 1.2.7, Vuo correctly handles the graphics thing passed in from VDMX when running compositions in the current process. The change will actually take effect with the subsequent release of VDMX incorporating Vuo 1.2.7. (Or, for now, substitute Vuo 1.2.7 into VDMX .)