This masterclass will cover new Vellum constraint features in Houdini 18, some of which are workflow enhancements. This includes automatically computing mass and thickness based on density, making it easier to work with geometry of different resolutions. Normalizing stress computations over substeps, will save you the hassle of having to adjust threshold values when changing substeps. For the new constraint features, there are Stiffness Dropoff, Tangent Stiffness, Stitch to primitive location, Sliding for Stitch and Attach constraints, and ARAP constraints which are effective for simulating organic material/softbody and things that require good stretching and compression behaviour.  


  • 00:03:58 Use autocomputation of mass+thickness
  • 00:12:04 Normalize Stress Computations
  • 00:17:14 Stiffness Dropoff with Stretch and Bend Constraints
  • 00:21:41 Tangent Stiffness
  • 00:27:26 Stitch Constraint Enhancements
  • 00:32:32 Sliding Constraints
  • 00:55:22 Triangle and Tetrahedral Stretch (ARAP) Constraints
  • 01:11:01 ARAP Constraints (Shelf Tools)
  • 01:17:41 Tetrahedral Stretch Constraints with Plasticity
  • 01:20:35 ARAP Constraints for Organic Behaviour
  • 01:22:44 Tetrahedral ARAP Constraints


  • Follyx 4 years, 3 months ago  | 

    indeed from a master...

  • benek 1 year, 9 months ago  | 

    Something I noticed when trying the sliding constraints setup is that Slide Scaling doesn't seem to work along a prim curve when going in the direction from start to end, ie when sliding in the direction from point 0 towards point 100, Slide Scaling just wasn't working, but when going in the opposite direction from point 100 to point 0 it works fine. I really had to pick the bones out of the example file to discover this one.

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