topic Re: sweep modifier with custom section in 3ds Max Modeling Forum

sweep modifier with custom section

bob.bernstein — Mon, 08 Aug 2016 23:08:45 GMT

Greets all, I've been suffering for a long time getting desired results from the sweep modifier when I need a custom section. Sometimes, it works after many efforts, yesterday I gave up. The sweep just would not work.

The problem is consistent, and I'm sure there is a predictable workflow, but I can't find it. Help simply says "pick your desired section"...life will be good! Except when the section is laid over onto its side prior to being swept. I had it happen with a somewhat complicated section, and gave up, resorting to just drawing a rectangle. Even then it would only sweep the rectangle along the path "laid over on its side". A rectangle on its side is just a line!

I thought the answer was just to trace the desired shape with a new line, which makes sure the vertices are nicely ordered, because that fixed the problem "once". But not yesterday.

The adjust pivot control gives you control over one axis, but the darn modifier seems to generally alter the sections orientation in the one axis that the rotation spinners don't impact.

Any help?

Best,

Bob Bernstein

Re: sweep modifier with custom section

PROH — Tue, 09 Aug 2016 15:29:22 GMT

Hi. Haven't had this problem with the sweep modifier ever. To me it sounds like you're talking about "Loft" where this happens often. So are you talking about the Sweep Modifier?

No matter what, I think it's a matter of workflow. When using Loft, it's recommended to draw both the line and the shape in Top-view. When using Sweep it's recommended to draw both line and shape in perspective view. Personally I mostly use the "Front-view" when using the Sweep modifier (IIRC). Besides that the selected reference Coord. System might make some differences.

Hope it helps

Re: sweep modifier with custom section

bob.bernstein — Tue, 09 Aug 2016 17:23:45 GMT

Thanks for your response. I tried to replicate my problem to show you screen shots, but of course my examples worked correctly. The max I still have on my laptop is 2015. The problem I experienced on my dev computer was using 2016. Too many moving parts to know if that is an issue.

I've also heard about using top down view in loft, but never any advise on most reliable workflow practice with sweep. You referenced using perspective view for drawing the custom shape...yes? I hadn't heard that.

Wouldn't it be amusing to find that's all I needed.

Best,

Bob

Re: sweep modifier with custom section

PROH — Tue, 09 Aug 2016 18:07:52 GMT

Hi. The "perspective view" advise is from the 2017 helps files. As said, I'm mostly using the front view, because back then when Sweep was introduced in Max, that was the "best way" using Sweep (IIRC), and then it simply became a habit.

The few times I've had problems with odd interpretation of the shape with the Sweep modifier, the reason has been that the shape was derived from an CAD or BIM import. The problem was solved by using the Reset X-form utility on the shape.

Hope it helps

Edit: In those cases were your shape is being projected sideways, you can fix it by rotating the shapes spline 90* on sub object level.

Re: sweep modifier with custom section

bob.bernstein — Mon, 15 Aug 2016 19:17:15 GMT

The subobject rotation seemed to miss the one axis that was wrong.

No joy, ended up giving up and using a straight line as the sweep custom shape, and then using extrude to accomplish my end goal.

Thanks for offering help.

Bob

Re: sweep modifier with custom section

PROH — Mon, 15 Aug 2016 20:15:45 GMT

Hi. I don't understand what you mean by "miss the one axis" in sub object level. I'm talking about rotating the spline on sub object level. What are you talking about?

Re: sweep modifier with custom section

Anonymous — Tue, 16 Aug 2016 05:00:44 GMT

I know exactly what the problem is because I've had this headache too and I solved it:

When you create your shape using your line tool, put an Xform modifier on it and then collapse the stack. I'm not sure if you need it on the shape or the sweep so I've just been putting it on both. I also make sure my lines are both editable splines (also not sure if this matters)
So the steps are:

1. Create shape (skirting/architrave) using line tool

2. Turn it into and editable spline

3. Put and x-Form modifier on it > then collapse the stack

4. Create a sweep after you've created another line representing where you want the sweep to go (also make this an editable spline)

5. put and x-form modifier on this too and collapse

6. Done! Play around with positioning once you're done to get it in the right place.

I believe the scale goes all crazy for some reason and this modifier resets it.