Corel 8 and Vector - Flat edged circles...Help!

[orb@twcny.rr.com]

Here's a problem that's been bugging me, and not being anywhere near as proficient in Vector as I am in Corel, I can't get a good handle on how to solve.

Sometimes (most times) when I layout a design in Corel and then import it into Vector as a DXF, my nice bezier curves and circles end up being an ugly collection of straight lines that are put to gether in a "circular" shape. I know there has to be a way in vector to fix these paths, but either I can't find it, or I'm doing something wrong.

If anyone can tell me how to deal with this, I'd really appreciate it because my arms are getting tired from all the sanding
.

Thanks,
RandyT

[danhamm@abccom.bc.ca]

Randy, I would wager good money that your problem
is either in your video card or configuration!

If you have your resolution set at 16K try 24, or 32 bit. res. if that don't work try turning down your hardware acceleration, if you are using
win 98.. I have encountered this problem with
some video cards ATI, and Nvidia tnt.
some where to start....

[orb@twcny.rr.com]

I'll take that bet ;)

The thing that doesn't jive with that solution is that the lines manifest themselves on the cut parts. For example, I have a panel that has several 1.125" circles in corel draw. When it is exported to dxf and then imported to Vector, it no longer is made up of curves, rather many straight lines in a circular orientation. Then, when the part is cut, there are distinct corners inside the hole and the round part that I want to fit in the hole doesn't fit because of this.

Curved edges of my cut parts have exhibited this very same problem, leading to sanding to "round" them out. In Corel, it is a nice sweeping curve with only a couple nodes with smooth curve transitions, but something gets lost sometimes when going to Vector.

RandyT

[imserv@imsrv.com]

Vector does not modify a DXF file when it is opened. Corel is saving the file with facets, so Vector processes them that way.

There is a function in Vector to fit arcs to the kind of geometry that Corel produces. Select the geometry and then Draw-Spline-Arc Spline. There is an error tolerance, that should be set to .003-.005 to eliminate any visible changes in the outline, or leave it at .020 if using it on letters that are 1.5 inches or larger, as you will not get that much noticible distortion. You may want to select only the curved portions of the geometry as sometimes straight portions will get a noticable "bow" if you leave the accuracy too high. The default values are set to do a fairly good job on Corel text, as that was the original application that the arc spline was designed for.

This function can make a major reduction in the number of entities in Corel or even in Vector generated Tru-Type text outlines. Reduced entity counts will speed up the pocketing and offsetting processes.

[orb@twcny.rr.com]

Thanks Fred, that was the ticket.

Of course all that post-processing is going to be a real PITA. I'm starting to think that Corel isn't the tool for the job, which really hurts me since I have about 10 years of experience with it :/ .

I did make another discovery which I don't understand. If I take a normal circle in corel draw, convert it curves (giving me 4 nodes) and then *manually* insert 4 more nodes into the geometry, one at about the middle of each existing node, it goes into Vector and gives me a circle with plenty (maybe too many) nodes that makes a nice smooth curve.

Does anyone know how to get Corel to export geometry to DXF with more nodes without all the manual interaction?

Thanks for the help,
RandyT

[gfacer@istar.ca]

Randy,

I believe that vector 9.3 can metafile cut and paste, and that should solve the problem too. Fred would know for sure,

Greg Facer

[danhamm@abccom.bc.ca]

Randy,
I don,t use vector so can,t answer that question,
But I do inlays and a variety of small and large
jobs using corel 7 and 8 exporting as DXF then
use the shopbot converter, and have never encountered your flats or stepped sides..
so don't give up on corel yet..I have drawn circles just to test,1/4in. to 8in. and exported
looked at them in autocad and signlab and magnifyied them and they still looked good..

[orb@twcny.rr.com]

Greg,

The Metafile cut and paste worked perfectly. I wish Vector could actually load in a WMF but this will work as well, as long as I reposition my zero point. Thanks for the suggestion.

Dan,

I can't explain the whys or whens. I have drawn a circle, but just one, in Corel and exported it with no problems. Plenty of segments for a reasonable circle, but when it is a circle on a more complex drawing, it seems to lose detail. I'm thinking there may be limit on the total number of segments exported as a DXF. As a side note, I imported the file into TurboCad with the same results, but since TC supports a WMF import, I was able to do that and it worked fine. So, I'm concluding that it is some kind of limitation in the DXF export filter of Corel. Thanks for the info.

RandyT

[orb@twcny.rr.com]

It appears I spoke too soon.

In Vector (Version 9 I believe, not the new one) when I cut and paste from Corel 8 the geometry looks ok, but the scale is off. My 48" panel turns into a ~40" panel. Needless to say, this is not good.

Anyone know if the new version of Vector has this same problem?

Thanks,
RandyT

[gerald_d]

RandyT, In your three programs that you are using to produce the circles, Corel/Vector/Shopbot, the least likely one to change the scale is Vector. If your Unit Values in Shopbot are correct (checked with simple MX commands and a tape measure), then I would start looking more at Corel to find the problem.

Vector doesn't change scales, and it it isn't easy to do this by accident either.