I cannot extrude the letter S that is from edges imported from a dxf. Anyone able to tell me why? There are a number of other letters from same import that have the same problem. A few do work correctly.

Not on pc at moment...Any chance of seeing the dxf is all good there? Lines closed?
Where is artwork originating from??

--- if you zoom in on the artwork in a drawing package... it seems the control points on the chamfer corners
is not done right...very likely that is cause of the problem.

Hi, Charlie.

In the contour of the letter there are overlays of dots if you remove them everything becomes normal.
If possible, for MoI, transmit via PDF or AI format, so it turns out without overlapping points. This often happens in the dxf.

One of the methods of treatment is to spread the points by height and remove the extra ones either through the rebuild command or export import via PDF or AI format.

Thank you very much - I imported the AI version and it has no issues.

Hi Charlie, yes if you turn on control points those red squares you'll see indicate spots that have multiple control points stacked up on top of each other. The math that is used for NURBS curves doesn't really get along very well with that type of situation. The points are automatically adjusted slightly in PDF/AI format import to avoid this but not DXF format import. I can add that in though, can you please send me the .dxf file so I can test with it? (email: moi@moi3d.com or post here) Thanks.

- Michael

Hi Michael, I've since tested a few letter shape dxf exports from corel. None of them work (without REBUILD) asides one through one of my plugins. Guess what it's a polyarc one. Will email the files. Hoping we can get this working as smooth as the adobe import. That one shows no segmentation on the "letter returns/rim". We need to avoid rebuilding and i really prefer flexibility of dxf layers...direct "adobe" paste also works corel>moi fine through another legacy tool I use in a very old version of corel....

Hi, Michael.
It is enough to export the Charlie file to DHF, and the point overlays will remain.
Just in case, I attach an export from another program.

Hi WN, what program was this Text.dxf file exported out from?

It's got another problem in its "knot vector" part of the curve structure in addition to duplicate control points. It has internal knots with a multiplicity greater than the curve degree. It means the curve has "degenerate spans" which make a sort of dead zone around each bezier piece.

That's why it will have some pretty weird behavior if you go in and edit control points on it.

I should be able to remove those degenerate spans automatically as well though.

Thanks,
- Michael

Hi Michael, i often fix artwork coming from other clients, many are sign makers themselves. Usually if a letter changes a fill colour at a click inside a drawing package then you can assume the shape is closed and done ok. That was my 1st test,pass. However, i then noticed the chamfer not looking right I fixed all those imported back to moi and same issue. This is about importing files originating elsewhere.. I wanted a real test..fresh artwork...all dxf exports from coreldraw made with native font text converted to curves and therefore a closed vector curve. These all had same issues, might indicate the dxf is importing not quite right or points are not interpreted correctly on import. When doing extrude with these (as per Charlies original) it would create a square panel behind the shape. My polyarc dxf tool worked but unfortunately it did not give a smooth letter rim.

I originally requested the dxf file from Charlie as to me the chamfer control points did not look correct. A normal chamfer should have two nodes before the chamfer - not one at/on the point. Maybe to fully solve the issue is not just about looking at the origination, also what's going on with other dxf imports. Can post some files later...

Hi Stefano, the DXF files above have problems being used directly for NURBS calculations because they have control points where several points are stacked up right on top of each other on the exact same spot. (And the one from WN has another problem with the curve structure in addition to that as well).

That degrades some of the mathematical continuity properties of the curve which is not really a big deal when they're being used only in a 2D vector environment but it is a problem when trying to do much more elaborate mathematical calculations on it as a 3D model.

There is some processing that happens in MoI's AI/PDF import that moves stacked up points apart from one another a little bit and so avoids this problem when using those formats.

That same processing does not happen for DXF imports because in the past I've generally assumed that people using 2D vector drawing formats would transfer data over into MoI using AI or PDF format and not DXF format. I expected that DXF format would be coming mostly from 2D CAD programs, not 2D Illustration programs. So obviously that's not really correct and there are people using DXF format for transfer out of 2D illustration programs too.

So for the next beta I will set the same processing to happen on curves imported through DXF format as well. That has solved the problems with all the example files posted here in this thread, if you have other files which are also exhibiting this same problem please post them here or e-mail them to me at moi@moi3d.com so I can test the updated DXF curve processing to see if it fixes those too or whether those are some other problem.

There are other kinds of problematic geometry like closed curves that have little self-intersecting loops in them that are also not much of a problem for 2D illustration calculations but cause difficulty when used with more elaborate calculations in CAD. But those are not so easy to automatically remove as the stacked control point problem. Those can require manual cleanup to remove the self intersections before the curves will be suitable for use in 3D CAD.

I have no way of knowing which of these things you're running into without being able to test the files though.

- Michael

Hi Michael, Will post some files soon as not working...thanks for your feedback/attention on this.

Hi, Michael.

This is a CorelDRAW program, I usually use Ai or PDF, a few years ago I encountered this problem when exporting to dxf from CorelDRAW.
This format is often used by those who work with CNC, since CAM programs primarily work through dxf.

Here is another example of exporting to dxf with different version settings.

Hi Michael,

I have taken a simple impact font letter S and converted to curves.
Then exported selected as dxf.

> The attached 2000 file should show same/similar results to WN 2000 file.
> The polyarc dxf file is using an export tool, 0.1 tolerance on lines and arcs.

> The direct corel>moi paste jpeg is the best here but obviously not a dxf route
and currently you need a very old version of coreldraw (32bit) for it to work.
Im hoping to be able to get this macro updated but 'dont know when'.

ACAD 2000 - CORELDRAW:


DIRECTR PASTE - CORELDRAW LEGACY (32bit)>MOI:


POLYARC EXPORT:



Be nice if we can eventually get this to work with the standard Coreldraw
dxf version (which i believe is splines).

Hi WN & Stefano, thanks for the example files. The DXF spline output from CorelDRAW is having problems because of 2 things - one is control points that are stacked up on top of each other and the other is their conversion from beziers to NURBS has one more duplicated knot than what is necessary to chain beziers together.

The stacked up control points means that the curve has a 0 length first derivative. The additional knot making a knot multiplicity greater than the degree of the curve means the curve has degenerate spans in it. CAD programs are generally not expecting to work with NURBS curves that have either of these conditions in them.

However both of these are things I can compensate for and remove during the import. I have got that set up so the next beta will be able to use these curves ok without weird stuff happening although I would not recommend using the PolyArc variation for construction of 3D geometry because it has a lot of little pieces which are close to being tangent to each other but off by just a few degrees. So if you try to construct something off of that you'll end up with lots of little surface fragments. But that's to be expected, it's just that you should consider that to be used only for CNC transfer and not for CAD transfer.

- Michael

Really top work Michael! Look forward to it ;0)