Geometry forces

Geometry forces give you greater control over your model when using scene geometry. Example scenarios include vines crawling on a fence, a building preventing tree branches from growing near it, and roots growing in and around each other without intersecting. Geometry forces are accessed like all other forces (“Geometry” is just another type of force like Direction, Magnet, etc.) and perform the following tasks:

• Identify the geometry to be used (either a mesh asset or parts of the model itself)
• Position it in the scene (if it’s a mesh asset, model parts remain where they are)
• Embed it in the output (if it’s a mesh asset, model parts already are)
• Specify how things behave around the geometry (attracted to it, avoid it, ignore it, etc.)
• Specify what happens if anything hits the geometry (crawl around it, stop, etc.)
• Set the range around the geometry where it has an effect

Please refer to the sample model named “Geometry Forces/Geometry_Forces_Example.spm” for this section of the documentation. This sample model demonstrates how to use Geometry Forces using very simple models to help make a complicated topic a bit easier to comprehend.

Note

Collections were a technique used in version 8 and earlier to allow procedurally generated geometry to be routed through the mesh asset system for use with forces. This system has now been replaced by Geometry Forces. Earlier models that used collections will be automatically upgraded to the Geometry Force approach when loaded in version 9 or later. Such models may require touching up to complete the process.

Refer to Add and apply Geometry forces and to Forces for more information.