Fenolis

Okay it's probably not the bug I was expecting. I didn't notice that Pasting Relative References into the curve's coords field was pasting them as strings, and I guess converting a float value to a string has some...weird consequences like adding them together in a string field becomes a concatenation operation. Changing the pasted "chs()" into "ch()" resulted in the behaviour I was expecting, and the correct one. My bad!

Ah. I was replying to a comment >2 months old regarding the point sorting order. I thought perhaps sorting by uvs would cause the smallest number to always be in the same position. Edit: Cool model, by the way. Missing proper normals on the windows but I like the style!

Point Sort > By Attribute > uv?

I created a Curve SOP and used float parameters on a Null to control the curve's points. Strangely, when the float values are (rounded to) integers, the curve's points are located incorrectly. Attached short video demonstrating the bug. 2018-05-05 15-09-13.mp4

In order to ensure a smooth seam, the curve needs as many points as its Order to interpolate. By merging the two end points into one, it avoids a hard "Corner" vertex.

What is the difference between using the Skin SOP after the Sweep, as compared to using the "Skin Output" option on the Sweep SOP? I imagine you could do a PolyFill after skinning, then finding a way to subdivide that. Maybe with a PolyExtrude inset?

Attaching your scene is usually helpful, if you're allowed to do so. Most of the issues regarding use of the Cookie/Boolean(Updated version) node is related to the inputs you provide. If you provide contiguous surfaces (no holes) it usually works fine. Here is a thread you may find helpful: Boolean

Turn your process into a HDA at the SOP level, and be the change you want to see!

I had fun with the math shape. astroid.hipnc

looks like you did an inset after... PolyExpand3D!?

That was very helpful! Thank you! Here's a design using Polybridge.

Thank you for the link! I've actually seen that one before a few times, and while I feel that there are some good steps there I have come up with an easier process. You used bending to achieve the curvature along both axes, while I drew a curve profile for my tyre base, revolved it to create the tyre, converted it to a NURBS surface which I then swept my tread pattern along using the Creep SOP. The Creep SOP also allows for control over surface coverage quite easily, as well as making sure it is impossible to create any overlaps. I'm sure the way you generated the tread pattern is similar to mine, and will work in my process as well.

I would like to know if you have any ideas on how to start modeling a shape like this procedurally in Houdini: I've already managed to build the tyre with help from the Creep SOP, but if you have any techniques you'd like to share, I'd be happy to learn those as well!

You could always hack the height with a "n/bbox(opinputpath(".",0),D_YSIZE)" expression in the scaleY value of a transform node, where "n" is the height you want.

Is the aimed point on the same plane as the points your normals are coming from?