Troubleshooting Rendering

If you just rendered and see nothing but particles, it probably means that something is misconfigured and procedural rendering does not work.

Don’t panic! Here is a check list for rendering that will help you to fix this in a snap.

1/ Did you load the Golaem Crowd Render plugin?

To facilitate deployment on the render farm, Golaem Crowd has been splitted in two parts:

glmCrowd: main authoring tool
glmCrowdRender: plugin for procedural rendering

You need to load glmCrowdRender as well to be able to render crowds.

2/ Did you check the render settings?

We have introduced a special tool to check everything is ok. Just go to the CrowdRender menu (in the Rendering menu mode), and select "Check Render Settings".

If one of these lines show a "NO", you should first correct the associated setting before trying to render.

The meaning of these settings is explained in the following points.

3/ Did you check for error logs?

If you created a proxy and are using the right renderer, Golaem Crowd should output some errors or warnings in the script editor if something goes wrong,.

Just open it and check if Golaem Crowd reported something after you clicked on render.

Note that errors are often not outputed in the script editor but in the Output Window (because of the way some renderers works).

4/ Are you using the correct renderer?

It may seems obvious, but we tricked ourselves many times with this one. If you created a Mental Ray proxy and you are rendering with Maya Software or V-Ray, chances are it won’t be working good. Check you are using the renderer for which you created your proxy in the "Render/Render using" menu.

5/ Is the current frame valid / simulation exported?

To be able to render your crowds, the rendering proxy need some information about it. This information is stored in an external particle cache for each frame (see this blog post about procedural rendering).

If Golaem Crowd cannot find this file it will not be able to render and report a "Failed to open cache file" error.

If the file does not contain the frame you are rendering, your crowds will not be rendered.

To generate it, you need to use the simulation tool.

You need to generate a simulation cache (the default setting) and for Renderman or 3Delight, the RIB files.

For other renderer, the renderers file export is only needed for command line rendering

Obviously the CrowdField you are trying to render should be selected
Do not forget to check which frames you are exporting.
Note that because of the way Maya initialize particle systems, the first 2 frames are empty.

Note that when using motion blur, more than one frame is used for computation, so you should check that the end frame is greater than current frame + motion blur range.

6/ Has Rendering Types been assigned to EntityTypes?

When you export your simulation (see above), you should check for errors in the script editor. A typical error is "no associated rendering type", which leads to an empty cache. You can associate rendering types in the Rendering Types tab of the Asset Manager (see documentation or tutorials for more details).

7/ Are the .CAM and .CAA loaded?

Select the CrowdProxy and check if all the fields in the attribute editor have a value and if this value is correct.

The yellow values should be filled automatically by the simulation tool.

The scene name and frame rate are filled at the creation of the CrowdProxy. The scene name is used as a prefix for finding the cache files, so you should check that it matches the name of the exported cache files.

For the following advices, please note that each time you modify the setup in the asset manager, you should hit the Assets Manager save button before trying to re-render.

8/ Are there any other points to check?

You may encounter a "Failed to load the character file" error, which means you did not specified the FBX geometry file for your character. You need to select your character type in the Asset Manager and export it as FBX using the corresponding icon in the Asset Manager toolbar.

When you have specified a geometry file, you can also get the "Cannot find .fbx file..." error when rendering. In this case, it means that your renderer cannot find your template geometry and therefore cannot render your crowds. To correct it, you should open the asset manager and check the path to your .fbx file. If the path is not correct you can change it by selecting it and using the Relocate FBX file button.

Another cause for not seeing the crowd may be that you renderer will stop the rendering if it encounters an error, even if it is not related to the crowd. Make sure you fixed all errors like missing textures... before trying to render your crowds.

If nothing works, try to export your simulation as FBX (but with only a few characters). Open the simulation tool, go to the FBX tab, and check the enable check box. Look at the script editor and check for errors, then try to reimport the generated FBX files in Maya to see which geometry is passed to the renderer.

9/ Ok, I can see them now, but why are they all orange?

It means that your renderer cannot find the shaders referenced (by their name) in the asset manager.

Usually, all you have to do is to import the maya scene containing your source characters with all shaders in your scene so that your renderer will be able to find them.

When you import your character, Maya will automatically add a namespace. You should delete this namespace so that the shaders nodes names match with the ones described in the Asset Manager. You can use the Namespace Editor (Window/General Editor/Namespace Editor)

You should not hide the imported character, otherwise the shaders will be desactivated. You should just put the character out of view from the camera.

10/ I can see only part of my characters, why does it look like a Picasso?

In order to optimize the rendering time, starting from Golaem Crowd 2.0, you need to specify a bounding box for your character when adding it in the asset manager.

Open the asset manager and select the geometry group. You can see a Bounding Box property. You can adjust the size of this bounding box in the attribute editor and check it in the viewport.

Note that you should set this box big enough so that when your character take a different posture (e.g. raise his arms in the air), his whole body is still inside the box

11/ Ok it works, how do I get Motion Blur now?

It's easy, each proxy provide a Motion Blur checkbox to be activated plus some settings to configure the motion blur aspects (please refer to the user manual for their meaning).

Obviously, it works only if you activate also the motion blur in the render settings of your renderer.

For example, with Mental Ray

Here is the result with the previous Motion Blur parameters set in the render proxy (notice the blur on the arms of the left hand side characters)

Please note that when exporting simulation, you need to adjust your simulation start/end frame to the sequence you want to render + the motion blur windows size or else you could get strange behaviors (i.e. rendering never ends with Mental Ray, motion blur applied to the full bounding box with V-Ray...)

12/ How do I get transparency on my shaders in Mental Ray ?

You just need to enable the Refractions attribute in the Raytrace Options panel of your shader.

Look at the result on the glasses and hairs.

Golaem Crowd 2.6

Troubleshooting Rendering