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export to CNC


DDDesign

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David,

DO NOT try to use VW dxf outputs for CNC use. The way it outputs the dxf's will not allow you to use it directly. We have a Multicam CNC for woodworking and we use Enroute toolpathing software. We cannot import directly. We always go thru another program, in this case Rhino, to filter out all the crap and produce a workable file. Works every time. Tried to import into Mastercam and had the same problem. For ease of making a file to start with you can't beat VW. We have been using it since the early MiniCad days.

Accuracy is also a problem. Try this test.

1. Draw a rectangle 1" x 2"

2. Try to bullnose the end with the fillet tool.

3. VW will not let you radius the 1" end using a .50 radius. One fillet will be .50 and the the other will have to be something less to allow it to work. A big NO NO if you are outputting to any CNC equipment. Mold , tool and die etc would never use VW because of this type of behaviour.

Pretty pictures YES, usable dxf's NO.

We have had these problems with VW for years on the output side but put up with it because of the ease of use. Even with the filtering, it's still quicker than the alternative.

Call me at 814-734-7364 anytime to discuss woodworking CNC.

Thanks,

Tom in PA

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John,

Thanks for the reply. I have reported the fillet tool problem a while back along with a clipping tolerance issue that I was having problems with. No resolution at that time.

I can probably get you the toolpathing software we use for your testing. I am not the only one with this problem with VW outputs. I put up with it because it is so easy to use, in fact the only CAD software I have ever used in 18 yrs of business. I have developed work arounds for most of VW shortcomings, I just wish they could be fixed.

I'll keep you posted.

Tom in PA

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Tom,

Thanks for the info. When you 'filter ot the crap' in Rhino, what exactly are you doing? Are you exporting, or redrawing. If exporting, is this really going to solve problems like the fillet issue you described? If you're re-drawing in Rhino, wouldn't it be easier to start from scratch, although you did say that VW was easier. I don't use Rhino, as it won't work on a Mac platform, but it seems a pretty good 3d modeller, which is what I'm using VW for - designing furniture - although alot of it is flat panel - so maybe VW is better(export files are all 2D). What do you think? Can I ask -what sort of work do you do anyway? Do you know of an alternative to Rhino that I can use?

Another comment on your fillet issue - I've found the fillet tool sometimes a bit flaky, especially when incorporated (via extrusion etc) into complex 3d geometries. Sometimes I end up with solids that don' t want to render. I tried your fillet example, and found VW would let me generate the shape, however when comparing the curve to a plain circle there are discpepancies showing up at high zoom levels. Interestingly if you look at the end of a rounded rectangle, you get a different result again. And once you cut one end off it, it changes shape to equal the initial double fillet example!

The 3D fillet edge tool is even more unreliable. I've had some weird results sometimes...

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I don't have access to any CNC machines or their software so it's hard for us to debug. Do you know what problem they have beyond the fillet problem you mentioned?

We export splines for any polylines that have bezier/cubic vertices, so if they have trouble with splines you might need to limit your polys to corner and arc vertices. We had complaints before about exporting duplicate vertices (which were in the polyline, so strictly speaking it wasn't a bug), but I believe those are all filtered out now.

I will add a bug report for the fillet issue if I can reproduce it.

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I only import into Rhino and then export right back out again. I do nothing to the file at all unless I find some useless crap floating off in space. I just ran into this yesterday with a file where some holes were deleted in VW and don't show up at all but appear when exported. These are the types of things that really screw toolpathing software up. As far as the fillet issue goes if I really need the accuracy I just alter the file in Rhino, which I trust in working right,and then export for toolpathing.

Most of our work is also in 2D as we do all sorts of architectural millwork. Some is in 3D but we have found Rhino to be one of the better programs out there for all around use.

The VW fillet issue is a joke. This is a basic tool that should work flawlessly, the 2D tool that is. I can understand some issues with the 3D tools as they tend to be alot more complex but a 2D tool that has been here in use since the early MiniCad days should be no problem in VW 11.5.1.

Keep on truckin'........

Tom in PA

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quote:

Originally posted by tgm:

I just ran into this yesterday with a file where some holes were deleted in VW and don't show up at all but appear when exported.

If you can email me a file that shows this, I'll look into it. It should be impossible for that to happen, given the way things work internally. Are you sure you don't have two overlapping polys or something, with the hole in the bottom one and a solid fill on the top one obscuring the bottom one?

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John,

I will forward you two files from yesterday that exported garbage from another layer even though Layer and Class visibilities were set correct for all but the layer being exported. Evaluate and get back to me.

The export layer shows nothing but what I wanted exported but that's not what we ended up with on the final dxf.

Thanks,

Tom in PA

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