Autocad spline import bug

[pailhead]

I've been experiencing this for years and years, but i never bothered to ask around if there is a cure for it.




This image shows a bunch of lines and arcs that were drawn in cad. When i import them into max, at least one of them fails. I can't really figure out a rule to this, i do draw some over the others though. It's really hard to reconstruct these as they come from cad with only 2 points.

[raymarcher]

Hello,

You can try to import with Autocad legacy DWG listed in import formats, it respects spline shapes in a more refined way. Uou can always send me the AutoCAD file so I can take a look, I like these kind of problems.

[chriserskine]

you may need to convert the segment from line to curve in max.

also type regen in cad before importing may help.

and last think make sure its near 0,0,0 though it dosen't look like that problem.

[pailhead]

Well, it never occurred to me that the distance from origin may actually mess it up while its being imported. MOST dwg files are drawn at some ridiculous distances. Of course, i bring it back once i import it, but maybe it would make more sense to do it in autocad before importing.

Ray, send me your email via pm, and i can send you the file.

This is already a curve, just a misshaped one, i know sometimes they are set to lines, and still retain their shape when switched.

[raymarcher]

Yes, always move to origin in AutoCAD, setup a global shift, it is a small hassle but it avoids many problems, especially with models created in AutoCAD.

[DanielBrew]

You're right this bug has been there for years . It happens when a vertex is incorrectly set to corner instead of bezier corner.

It should be easy to fix though. You can set the vertex back to bezier corner and copy and paste the tangent from the vertex underneath.

[pailhead]

Can it be due to the order in which i draw the poly line in autocad? I just realized that i start some where the arc starts, and some i start where the straight line is. Basically, sometimes when i close them, my last point is the last point of the arc, i cancel the next arc by switching to line, and then instead of drawing another point i just close it (autocad). I'll test it.

[DanielBrew]

I forgot to add, make sure paste length is checked otherwise it only pastes the direction of the tangent.

[pailhead]

The main reason why i got annoyed was that i didnt have another proper spline underneath this one basically i have nowhere to paste from.

[DanielBrew]

I was looking at the image you posted but you're right there won't always be a spline with the correct bezier handles underneath to copy.

I think you might be onto something with the vertex numbering though. From memory the bug only affects one vertex per spline. Is it always vertex 1 in Max that is incorrect?

[pailhead]

I think its only one. I actually only encounter this when i model churches for my mother, but since i started doing that at 14, i've been experiencing that a lot

I like the way arcs come out of cad though, it's always just two points, at least when you're building arches, not sure what happens when you have more than 180 degrees. I try to be very consistent with my spline steps, so it's really painful to recreate these in max using it's arc. Here, i was fixing it by first tracing the arcs that came out good with max's own, then aligning dummy, or more often a rectangle with it's pivot, so i have something to snap to, and then building a circle from center point using that. Creates a nice 2 point arc.

[mikeh]

This has already been said but it can't be emphasized enough. if you are NOT moving everything to 0,0,0 BEFORE importing, then you are bringing in files that are corrupting your file in ways you may not even be aware of.
mh

[raymarcher]

Why don't you use the new egg spline to rebuild those arches, haha?