Chapter 10: Troubleshooting and scripting¶

10.1 Why did Definition change only one object?¶

Definition for Geometry, Collider, Site, Joint, and Actuator changes only the active object by default. To batch-edit, enable Apply to all selected in the dialog.

10.2 Target or Reference order is reversed¶

Deselect everything, then select again in the correct order:

• Equality: the first is Target 1/parent; the second is Target 2.
• Sensor Reference: the first is Target; the second is Reference.
• Targetbody Light: with one Link, that Link is the target; with two Links, the first is the Light position/parent and the second is the tracking target.
• Targetbody Camera: with one Link, that Link is the target; with two Links, the first is the Camera position/parent and the second is the tracking target.
• Tendon: Joints are added to the target list in selection order.
• Link Parent: the exception; the active object is always the parent and must be activated last.

10.3 Compute Inertial finds no geometry or fails¶

Ensure Inertial Model Type matches the intended Visual / Collider source and that geometry is a direct child of the selected Link, or inside its Frame descendants. Child Links are not searched. Mesh calculation requires TetGen; enable Check Geometry for validation and repair failures reported for the mesh. Box, Sphere, Cylinder, and Capsule use shape parameters directly and do not require TetGen. See 4.5.

10.4 The original object is no longer selected after creation¶

Most Creation Operators clear the original selection and select the newly created objects. This is expected. To continue creating child elements on the original Link, select the Link again.

10.5 Shape Size and Object Scale¶

Prefer editing Size, Radius, and Height in Shape Properties. Primitive shapes are normally controlled by Geometry Nodes Modifier parameters and lock Object Scale. After changing to Mesh, the geometry is baked into the mesh and Object Scale may become editable again.

10.6 Operator ID quick reference¶

Creation¶

Definition¶

Utility, IO, and CoACD¶

Properties¶

Properties operators use the common forge.properties_* naming scheme, including global, visual, hfield, plane, shape, shape_site, link, joint, actuator, tendon, equality, contact, sensor, light, camera, and replicate.

10.7 Blender Python example¶

import bpy

# Ensure Object Mode and deselect every object first.
if bpy.context.mode != "OBJECT":
    raise RuntimeError("Forge operators require Object Mode")
bpy.ops.object.select_all(action="DESELECT")

bpy.ops.forge.create_geometry(
    geometry_type="BOX",
    size_box=(1.0, 2.0, 0.5),
)

Operator calls are constrained by the current Blender Context and poll conditions. Before batch operations, set explicitly:

• Object Mode;
• the selected objects;
• the active object; and
• the Forge selection order when two targets are required.