Jeff Lait


About Me

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My Tutorials

obj-image Masterclass
Houdini 16.5 Masterclass | OpenCL
obj-image Masterclass
Houdini 16 Masterclass | Heightfields
obj-image Masterclass
Houdini 16 Masterclass | Compiled SOPs
obj-image Masterclass
H15 Masterclass | Grains
obj-image Masterclass
H15 Masterclass | Loops
obj-image Masterclass
H15 Masterclass | Distributed Simulations

Recent Forum Posts

attributes that drive vellum Oct. 17, 2018, 9:46 a.m.

Not yet…. I'm making a list and checking it twice, so hopefully it will show up soon.

There is no per-point friction, however, so that attribute isn't on the list.

You can also look at the help for the Detangle SOP to see some of the collision attributes described.

Most dynamic attributes are covered with the POP Attributes docs as there is a lot of overlap.

atrribdataid array length Oct. 16, 2018, 9:11 p.m.

It's a 64-bit session id broken into two 32 bit integers. So it will be the same for all data ids you read within a session.

Dive into the Vellum Solver SOP where we recompute the graph colouring to see attribute ids being used.

Vellum, grain-grain collision exclusion when explicitly constrained? (and non-disablable collisons!?) Oct. 15, 2018, 8:11 p.m.

It might help to clarify that the detangle and the grains are two separate collision detectors in Vellum. The detangle uses overlap and disableself, but the grain colliders do not. The grain collider uses the isgrain attribute to include a point for grain collision.

The collide mutually constrained isn't in Vellum. Often it was used in grains to handle sheets or wires where one has to have a very dense layer to avoid penetration. In Vellum, it is expected instead to just use triangles and lines for this. The main reason for its absence, though, is that the constraints live on a separate geometry in Vellum.