topic Re: Sweep twisted in 3ds Max Modeling Forum

Sweep twisted

AD_GW — Fri, 11 Feb 2022 18:33:09 GMT

Hey,

I try to solve this pretty basic problem, but can´t figure out how to fix it.

I´ve got a rectangle spline with a sweep modifier on top. When moving the vertices on one side the sweep gets weirdly twisted.

So basically I try to get the result from the last object, without rotating the object.

Anyone knows how to avoid this twisting?

Thanks and br,

Gerald

Re: Sweep twisted

AD_GW — Sat, 12 Feb 2022 10:01:06 GMT

Same thing happens if a SplineMirror modifier is applied to a sweep-object

Re: Sweep twisted

10DSpace — Sat, 12 Feb 2022 17:20:03 GMT

@AD_GW

Not sure where in the stack you are trying to manipulate the vertex, but try putting an edit poly modifier on top of the sweep modifier and move the vert at this top edit poly's sub-object level. Bear in mind you will need to have enough topology/edges for a smooth result when you move the vert.

Re: Sweep twisted

AD_GW — Mon, 14 Feb 2022 07:41:31 GMT

Thanks for your reply.

I would like to be able to change the sweep profile later, so adding a edit poly is not a solution.

Also just moving the vertices straight up would also yield a somewhat deformed profile.

Not sure how sweep modifier works internally, but it seems to depends on some vertex normals(?) which we don´t have any controll over and also are not possible to recalculate.

This is bugging me for years, but I usally use a workaround or avoid it, but right now I´m working on a script that heavily depends on sweep and I would like to find a more staight-forward solution.

Re: Sweep twisted

leeminardi — Mon, 14 Feb 2022 17:08:04 GMT

Try adjusting the Angle value of the Sweep Parameters. The top geometry is the spline with a vertex moved backwards and the bottom shape is a copy with its sweep angle modified.

Re: Sweep twisted

AD_GW — Tue, 15 Feb 2022 20:12:43 GMT

Thanks for the tip!