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cropwell
02-03-2016, 11:25 PM
Ey up chaps, I'm stuck.

I have got a very old version of AutoCAD loaded on my CNC computer, which has no unnecessary software (networking etc), so the easy way of explaining my problem is to start with a photo of the screen
17787

What I am making is a harmonica case. The inside cutout is two rectangles and two circles. I want to end up with a pocket which is the combine of the four shapes. I can do the drawing in Coreldraw, and weld up the shapes, but when I transfer it to the CAM program (EstlCam) it produces a very 'steppy' outline, which is no use. I have to export the drawing to a .dwg file with Corel and then open it in AutoCAD and export it as a .dxf file to go into Estlcam. Somewhere in this process it loses the continuity of the shape.

How do I make the four shapes into one outline ?

I must admit that I do not understand the AutoCAD terminology. The program was bought for my son when he was a student in the late 1990's and I am unwilling to spend money on a CAD program, when there are so many free ones about and I am unlikely to use them to any worthwhile extent.

Cheers,

Rob

cropwell
03-03-2016, 12:04 AM
Sorted - after a lot of messing about !

Blackrat
03-03-2016, 04:32 PM
iirc you type in the word TRIM :D

suesi34e
03-03-2016, 05:39 PM
Hi, sorry I meant to PM you!

cropwell
03-03-2016, 06:44 PM
I have got past the stage of creating the shapes I need. Now I find I can't make them into a dxf file to put into my CAM program. All I get is the outer rectangle. I attach a copy of the dwg file, if anyone can help. The inside shape was created as a REGION and then made an outline with the UNION command.

Here's the dwg file 17799

Clive S
03-03-2016, 06:51 PM
Rob are you trying to convert it to DXF if so here it is

17800

cropwell
03-03-2016, 07:15 PM
Thanks Clive, but I was hoping to find out why I could not do it, What the Fun was I doing that the export command did not pick up the inner bit?

I need to know so that I can do other drawings through the same process.

Cheers,

Rob

Clive S
03-03-2016, 07:23 PM
Rob was load it into Acad and saved as dxf in your version.

I don't understand why it does not do that for you.

cropwell
03-03-2016, 07:53 PM
Rob was load it into Acad and saved as dxf in your version.

I don't understand why it does not do that for you.

Maybe because I have a very old version of AutoCAD (R14). It only gives me the .dwg or .dwt option on save as. DraftSight does not export the file either. I thought it might be because I had to create a REGION to combine the shape and this put it on another layer or something.

I tried 'Save As' .dxf in DraftSight and that did not work properly as well.

I reckon it is because I feel knacked at the moment and everthing is working to Sods Law. If I have a fresh go at it over the weekend, I might see what is happening.

Cheers,

Rob

Robin Hewitt
04-03-2016, 11:01 AM
I tried importing Corel to AutoCAD and it was exceedingly messy, Instead of lines and arcs I got some bizarre Bezier shapes the AutoCAD could barely understand and I did not like at all.

Ger21
04-03-2016, 04:57 PM
Thanks Clive, but I was hoping to find out why I could not do it,

Because it's a REGION.
Explode the REGION, and use PEDIT to Join the lines into a single polyline.

Always save as V12 .dxf, for best compatibility.

cropwell
04-03-2016, 07:20 PM
Because it's a REGION.
Explode the REGION, and use PEDIT to Join the lines into a single polyline.

Always save as V12 .dxf, for best compatibility.

Thanks Ger, I have sorted it now. I must admit to my ignorance in using AutoCAD. I need a good tutorial and the timeand brain energy to go through it.

I am using AutoCAD from the '90's R14, so saving as anything other than a .dwg is not an option, and V12 is not in the export options list.

BUT I did what you said (I suspected it was the REGION problem) and it worked after a couple of fumbling attempts.

Cheers,

Rob

Ger21
04-03-2016, 07:43 PM
I haven't used R14 since around 1999, but it should certainly save as R12 .dxf. Even current version still do.
Try using File >Save As, and click on the drop down list for file type. R12 should be the last one?

cropwell
04-03-2016, 08:13 PM
I haven't used R14 since around 1999, but it should certainly save as R12 .dxf. Even current version still do.
Try using File >Save As, and click on the drop down list for file type. R12 should be the last one?

Sorry Gerry, but 'Save As' only give R14, R13 and R13 options as .dwg and the other option is a drawing template file .dwt.

EXport works fine though and I now have created a .tap file from the drawing and am ready to do a test cut.

Cheers,

Rob

Ger21
04-03-2016, 09:03 PM
try typing DXFOUT in the command line.

cropwell
04-03-2016, 10:31 PM
try typing DXFOUT in the command line.

That works !


I tried importing Corel to AutoCAD and it was exceedingly messy, Instead of lines and arcs I got some bizarre Bezier shapes the AutoCAD could barely understand and I did not like at all.
Again with Coreldraw I have an old version and do not intend to waste money upgrading. It does not translate to .dxf at all well. It seems that all lines have thickness and that causes twice the gcode and a lot of unneccesary cutter movement. Also curves are 'blocky' or 'steppy', however you like to describe it.

I have tried DraftSight, but that seems to be just a budget (free!) AutoCAD clone, nevertheless useful for what it is.

Cheers,

Rob

Robin Hewitt
05-03-2016, 09:41 AM
The trouble with AutoCAD comes when you create a mesh. At point of creation you have to define how many facets the mesh will have and you cannot go back and edit. You have to redraw if you want to change it. Each ENTITY can have completely different facet settings and they do not SCALE well. If you can stick to lines, arcs and circles then everything is fine and dandy. You can project lines and arcs into 2.5D by changing their THICKNESS but for real 3D work you need Solid Works or the clone thereof. That will allow you to adjust the facet angle and size parameters on the fly when you export the finished shape. CorelDraw is not an engineering product and should not be treated as such, it is for making pretties. You should only use it when pretties and engineering collide, usually realising graphic art and making signage.

I do like a good rant on Saturday morning, sets me up for the weekend. I shall go and blast 50 clays out of the sky with an antique muzzle loader tomorrow morning, bliss.

Ger21
05-03-2016, 12:18 PM
I doubt that you'll find many people modeling with old style meshes in AutoCAD in the last 10 years. Meshes definitely have their place, if you understand and know how to use them.
But for the last 10 years, AutoCAD has become a very powerful 3D modeler, with a lot of new modeling features.
Lofting, nurbs, mesh subdivision, smoothing, solids. I would say that you can do at least 90-95% of what Solidworks can do in AutoCAD, if you know what you're doing.
THe biggest problem with 3D modeling in AutoCAD is that you need a pretty powerful PC if you're doing complex models. Until last year, I've done all my modeling in AutoCAD. But now I'm switching to Fusion 360, which is far more capable for 3D work, has built in CAM, and is about 15% of the price of AutoCAD. (And free for most hobbyists).
But I still use AutoCAD for my 2D machining. AT least until I have time to learn more about Fusion's CAM.

cropwell
05-03-2016, 01:55 PM
Have I opened Pandoras Can of Worms ?

graffian
05-03-2016, 04:54 PM
You need to buy an autocad R14 book, it just so happens.............