Sweep modifier problem

[wanderer]

Hello. I encountered a problem when trying to apply sweep modifier to a closed curve bending in 3 dimensions. In my case it is rectangle. The result looks like line is not closed but I used weld to ensure it closed. Does anybody know that issue? Thanks.

[Scott Schroeder]

If you select what you think is one vert, does max say you have one vert selected? Often times it may not weld the verts together and you won't know it until you either do a shape check to make sure you don't have an open spline or you select your verts individually.

 

Other than that, posting screen caps of your issue will help get your a lot more responses. It's difficult to explain in words what an image can clearly show.

[wanderer]

Thanks for reply, Scott. I checked all corner vertices welded. What I noticed that it happens on the inside of the curve and when profile gets bigger. Here is a screenshot:

 

Uploaded with ImageShack.us

[wanderer]

Thanks for the reply, Scott. I checked all corner vertices welded. What I've noticed it happens on the inside of the sweep line and when profile gets bigger. Here is a screenshot:

[wanderer]

Thanks for reply, Scott. I checked corner vertices welded. I noticed that it happens when sweeping on inside of the curve and when profile is rather large. I don't know what I'm doing wrong but moderator is blocking my post with attached screenshot.

[wanderer]

Here is a screenshot. Couldn't get it from imageshack so used attach.

[Scott Schroeder]

It looks like a loft/sweep with the lofted shape's pivot point wrong. Say, for example, if you create the shape in the left view port it will loft it flatten out. If you create the shape in the top view port, it will loft/sweep correctly.

 

A few quick fixes without having to recreate your shape. If this is a loft, is to edit the rotation of the lofted shape in the loft. Select the loft modifier, select shape, and rotate it. Though be careful, this is a step that can't be recovered by an undo. Once you rotate it, you are locked it.

 

If this is a sweep, you can use the rotate shape dialog in the sweep controls.

[wanderer]

I'm talking about sweep modifier. Yes, it seems like a pivot problem and as I said early it happens when sweeping inside of the curve. I know I can tweak it to use outside but I wanna know clarify is it work either way or it's just my issue.

I've attached max file where you can see what I mean. I used rectangle and shape merge object to project it on sphere.

Would be great if you look at it.http://www.mediafire.com/?oj4lppmihra773a

[abhaysingh]

Hi Roman,

Did you find any solution ?

It seems like you've used "shape merge" tool to merge rectangle on a sphere & then extracted those edges as linear shape.If it so then it is not a rectangle anymore.It will create problem with sweep.Try deleting the vertices adjacent to the corner ones.May be I am totally wrong

Edited April 25, 2013 by abhaysingh

[H A]

A quick fix that worked for me a couple of times; Create a new spline in top view, attach the old spline to this, delete the new element and reset pivot. After that it might work, you may have to reset xform.

[wanderer]

Hi Abhay. Yes, I used extracted shape of projection created by shape merge object. Adjacent vertices aren't very close to the corners and logically by deleting it I'm losing curvature of the sweep. Unfortunately, I can't upload a scene cause for some reason moderator is blocking my external links.

So my question is still there. Is it problem of sweep modifier?

[wanderer]

Hey, H A. It doesn't work for me.

[abhaysingh]

The problem occurred because of the extra vertices which came after extracting the shape from mesh.It will never happen with rectangle having 4 corner vertices.Basically, the corners are too tight with vertices so the mesh is intersecting.Please see the image attached for vertex placement.You can either try deleting vertices adjacent to corner ones or you can try & decrease the width of "custom section type" used in sweep modifier.For sweep modifier rule -- "The width of "section type" should be less then the distance of adjacent vertices from the corner ones & vice versa".

Please correct me if I am wrong.

 

Abhay.

[wanderer]

I think you are right, Abhay. When you use sweep on outside of the curve those adjacent vertices are getting farther from each other and all looks fine but when you are sweeping inside, vertices are getting closer as path shrinks and when the width of the profile doesn't fit this distance, overlapping occurs. I suppose it just as sweep works.

Thanks for helping to figure out.

[abhaysingh]

Yes, that's how it works.