CAD Software Forum

I asked this question directly email but got no answer so I'll try here:

I frequently draw small templates with AcadR14 that are straight on 3 sides, but they have a shaped fourth side that might include curves and straight lines that begin and end on their common end points.
After I draw the shape with individual entities, I then change layers and come back and draw the entire shape as just one Polyline that starts and ends on a corner.

I then Fit/Curve that Polyline and it immediately fits itself into an exact match to the original shape, but composed of only one single Polyline.

Now here's the fun part: First, the reason I do that is so that when I send the dxf of that entity out to my CNC cutter, the CNC path is just one path and it can cut the outline without lifting and starting on each endpoint.
The ONLY way I can achieve that result is that when I do the single Polyline in AcadR14, I snap twice on each endpoint so that when I Fit/Curve the Polyline, those double snapped junctions allow a straight section and a curved section to exist next to each other and maintain their intended straight or curved shapes.

When I do the exact same thing in CMS/Intellicad, the double snap points are ignored and the entire shape goes into a Fit/Curve where I lose all of the individual shapes.

I hope that makes sense by my description and I wish I was able to post a graphic here on the forum to better show what I'm talking about.

This is kind of a deal-breaker for me because I do a LOT of these template drawings and I can't figure out a way to make Intellicad work like my ancient old AcadR14.

Thanks in advance,
Carter

Why not skip the whole second layer thing and use pedit to join the original shape into a polyline. Lot less work.

I could do that, but then I'm afraid I could lose control over the start and stop points of the entity when it gets converted to G-code.

After seeing your reply, however, you got me to thinking so I went back in and played around with various workarounds (such as Joining). What I came up with actually gets me to where I want to go, but then I get a new problem.

What I did was to snap over my original drawing starting at the corner I want the CNC cutter to start at, and then follow my original drawing around by using using the "Arc" and "Line" sub-commands within the PLine command.
That allowed me to do what I wanted to where I ended up with an exact repro of my original design, and I didn't have to use the "FitCurve" command to get the shape. (I tried it for fun, and the FitCurve command screwed everything up).
So, I've got that part nailed down, but here's my new problem:

Once I draw the exact shape I need, I always Offset the PolyLine by .032 to the outside in order to accomodate the 1/16" cutter of my CNC machine.
But when I went to offset this particular PolyLine, I got the message that "The entity curves too sharply to offset to this side using that distance".
So then, I closed the drawing (as an AcadR14 drawing), opened it up with AcadR14, and tried again to Offset the same entity by .032 and in Acad, it now worked and offset perfectly.

So now where am I at? I did some more playing around in CMS-Icad but couldn't find a workaround. Considering the supposedly seemless compatibility between Acad and Icad, I dont' understand why such a simple command can't be done in Icad but can in Acad.

Sorry if I seem to be pickin nits, but I'm trying very hard to get to the point where I can use Icad exclusively, but the direction I'm going, it's looking more like I might end up letting Icad go and go back to Acad exclusively.

Carter

I can't say as I have ever had the offset problem. I assume that you are using a waterjet. 1/6" would be a bit wide for a laser and quite small for a mill. Do you actually load this and run it yourself or does someone else do that? Reason I ask is, there has to be some way of specifying tool path at the machine. In that case, I can't see why a completely closed shape would be a problem. When specifying the tool path, the start and stop points should be easily difinable. Can't really say as some of these low level machines are quite simplistic. In any case, the problem now being offsets. I don't know what to say except if R-14 is working for you, I don't see any reason to change. EDIT: I looked into this a bit further. I have been able to duplicate the offset problem. Tried the same darwing and offset in Turbocad and Autocad. Both worked, though if the offset was equal or greater than the radius, it would result in distortion of the offset line.

[This message has been edited by CW (edited 06-25-2005).]