topic Re: Spline Stroke in 3ds Max Programming Forum

Spline Stroke

MehdiZangenehBar — Wed, 13 Mar 2024 22:44:17 GMT

What is the correct way to create stroke along a path (spline)?
My goal is to create a modifer using scripted plugin that will accept a spline and ouput a (2d) geometry or shape. something like this:

Re: Spline Stroke

klvnk — Thu, 14 Mar 2024 11:25:44 GMT

what's wrong with the sweep modifier ?

Re: Spline Stroke

istan — Thu, 14 Mar 2024 23:02:21 GMT

how about spline thickness?

Re: Spline Stroke

MehdiZangenehBar — Thu, 14 Mar 2024 23:48:20 GMT

nothing, I just need to create from scratch to have full controll to add some more features, for example:

And so much more, So I need to create my own.

Re: Spline Stroke

MehdiZangenehBar — Thu, 14 Mar 2024 23:50:02 GMT

I need more than that. I just mentioned the start point.

Re: Spline Stroke

klvnk — Fri, 15 Mar 2024 01:03:28 GMT

the third one and the last are probably best done as different modifiers the last is best done as a "rail" modifier ie 2 splines to describe the outline shape . the 4th is just a delete mesh mod on top of the mod ( or 3 seperate meshes 😕 )

the trick with these kinds modifiers in the sdk is to use the polyline (the visual representation extracted from the bezier) as the basis and not the actual bezier. Unfortunately to my knowledge this is not available in mxs (though you can approximate it). You then compute all the frenets (search the sdk and theres multiple versions) (array of xforms) a basis xform (computes the tolocal xform) as you can have more than one spline. There some really tricky maths for keeping a constant cross section (not included in the sdk versions 😐 ) and some post processing funkiness to make sure everything connects nicely in the case of a closed spline.

Re: Spline Stroke

denisT.MaxDoctor — Fri, 15 Mar 2024 08:16:30 GMT

The 2D version is very easy to implement in MXS. I would do it as SimpleObj - a spline is deforming a plane..... For a 2D spline, it is very easy to get a matrix in any curve parameter. This matrix should be used to transform the vertices of the "plane". A curve controls or Bézier controllers can give the scale and offset.
I remember a very similar plugin I showed in CGTalk.

I also remember a very good example of a plugin from Swordslayer on a similar theme.

Re: Spline Stroke

denisT.MaxDoctor — Fri, 15 Mar 2024 08:22:54 GMT

Another simple solution is to use the "Rendered" spline with the "Rectangular" option. Remove all unnecessary and tessellate what you need.

Re: Spline Stroke

MehdiZangenehBar — Fri, 15 Mar 2024 10:28:29 GMT

Yea, 2d version using simpleobj does the job I think, would please repost the sample here, sadly we don't have access to CGTalk archive anymore.

Re: Spline Stroke

MehdiZangenehBar — Fri, 15 Mar 2024 10:34:17 GMT

Yea, I need them all in one modifier, and yes I need a new shape or mesh at top of the spline.

Re: Spline Stroke

MehdiZangenehBar — Fri, 15 Mar 2024 10:36:07 GMT

C# version using Autodesk.max.dll also works for me.

Re: Spline Stroke

istan — Sat, 16 Mar 2024 23:41:28 GMT

I'd use simple splines and would create the mesh on my own - but C++ has "better" access to splines, imho.