Guide Geometry

Most of Carbon nodes have Guide Geometry allowing some degree of visualization of the object or constraint created.

Some nodes have these enabled by default (the Carbon Rigid Body node for example) to allow rapid setup of their properties. For the nodes that haven’t, don’t forget to turn them on in order to speed up the troubleshooting of your scene.

Other nodes (the Carbon Cloth node for example) also have special Carbon Cloth Guide Geometry tools to visualize and assess the suitability of the geometry for simulation.

Output Console Messages

When the simulation Output Console Messages toggle is on, a report will be output into the console window every time a Carbon Simulation node is re-initialized.

This is extremely useful to understand why some of the Carbon nodes don’t produce the expected result. Especially with the Relationship Nodes which can be more difficult to setup.

If you don’t need the console output, simply toggle off the Output Console Messages.

Simulation Not Starting

There can be several situations where the Carbon Simulation plug-in is not running as expected.

Assuming that the installation process hasn’t been interrupted or tinkered with, most of the time it will be because of a license problem (not enough licenses available or no valid license file has been found). This scenario is usually quickly diagnosed by looking for an error message in the output console such as: No SIM_CarbonTool license available. Additionally, the SOP Carbon Simulation node will also be shown in a warning state. If you are using an evaluation license you can contact for help setting up your license. If you are using floating licenses, it is probably best to contact your company’s relevant systems/IT department who should be in charge of managing your licenses.

The second most likely cause of problems is an incompatibility between the Carbon plug-in version and the Houdini version. It is possible to run a Carbon plug-in that has been built with a different Houdini version for as long as the Houdini binary compatibility hasn’t changed between these two versions. When the binary compatibility is broken, the Carbon plug-in won’t load. This is apparent when the high level Carbon nodes are showing some warnings or errors because of missing Component Nodes. Unfortunately it is not possible to know in advance when the binary compatibility has been broken by simply looking at the two Houdini version numbers. If you have such a problem, you can try with another Houdini version or request a compatible build by contacting