CREATING CUSTOM ATTRIBUTES TO DRIVE GUIDE STRENGTH OF MATERIALS

1 For more precision and control, a custom point attribute can be created and remapped within the RBD Bullet Solver. Because glass would likely shatter and unguide sooner than concrete would break apart, a point attribute called ‘@ guide_anim’ was created and applied to glass pieces only. To create the guide_ anim point attribute, drop down a point wrangle and insert it in between the proxy geometry and RBD Bullet Solver path, as the custom point attribute needs to be on the simulated geometry to have an effect. In the Vexpression write ‘f@ guide_anim = 1;’. This ensures all pieces will have a value of at least 1 when working with material groups down the line.

2 Drop down another point wrangle to change the attribute for the glass pieces. The fractured proxy geometry has groups associated with the various materials, so within the point wrangle, the glass group was selected to be operated on. Within the Vexpression of the point wrangle write ‘f@guide_ anim = 0.125;’. This should overwrite the guide_anim attribute for glass pieces.

3 To remap the guide_ anim point attribute to the Guide Strength parameter, select the RBD Bullet Solver and under the Guided Simulation tab, check the Use Vexpression toggle within the Setup tab. Write ‘strength *= @guide_ anim;’. This will multiply each pieces guide_anim point attribute by the current Guide Strength parameter within the solver, resulting in pieces with a guide_anim attribute value below 1 to unguide faster when collided with.