Sweep along topology has corner issues... How can I fix?

[jessela]

I'm snapping a path along a terrain and then using that path in a sweep node as a backbone curve to generate a wall. The problem I'm running into is that the sweep is following the tangent of the terrain normals and creates a warped look in the corners that's accentuated with increased height.
I tried to correctly orient the cross sections in the sweep node by using an orientalongcurve node with the snapped path in input 1 and the pre snapped path transformed higher in y for input 2. That works more or less for the longer portions of the wall but still results in warped corners.

Since this is a wall and not a roller coaster, is there a way to force the cross sections to always be oriented straight up in y while still following the snapped path around the terrain? My assumption is that this would fix the corner issue, but I'm very new to Houdini so I may be going about this all wrong. Any help would be very appreciated.

[jessela]

I found a partial fix. Using an attribexpression node with Normals turned on and a VEXpression of set(self.x*1, self.y*0, self.z*1) fixes the normal direction, but I'm still getting a good bit of pinching in the corners. Stretch Around Turns in the sweep helps a little, but not much.

[Fenolis]

Does this work for you?

 

sweep_wall.hiplc

[jessela]

It keeps things straight in y, but it's still getting pinching in the corners. That's that main thing I'm trying to figure out now is how to get a clean corner.

[Atom]

That's just because your copies are close together. Try setting the Length on the resample to 1.0. Also review your curve to make sure the angles bend at 90 degrees as you would like. You may want to sweep the wall, before conforming to the terrain.

[Aizatulin]

Sweeping the wall before conforming the terrain is working well for me. You can use curve attributes (like curveu or pointnumber) to determine the difference in y between the planar and the projected curve.

@edit: instead of only y, you can also use the whole difference vector (delte_x,delta_y,delta_z) between both curves.

 

 

sweep_mountain.hipnc

Edited December 17, 2021 by Aizatulin