Machsupport Forum

G-Code, CAD, and CAM => LazyCam (Beta) => Topic started by: dbvogt on July 18, 2009, 04:13:14 PM

Title: Lazy Cam doesn't create true arcs - makes straight lines
Post by: dbvogt on July 18, 2009, 04:13:14 PM

Lazy Cam (demo) is somehow improperly importing a DXF drawing of 6 sections to cut out of a disk to create 6 spokes for a wheel. The outer and inner parts of the sections are circular but LCam draws the outer border as three straight lines per section. I thought  this was just the resolution of the tool path window in Mach but running the G Code shows the spindle actually does follow the straight lines rather than a proper arc of a circle. According to someone who loaded the drawing in Autocad, it looked OK.

Is the  licensed version required to do this? If not, how can I increase the number of steps in the G Code to create a true arc of a circle?

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: Chip on July 18, 2009, 04:22:18 PM

Hi, Dbvogt

Post your dxf, I don't think it's a lic. issue

Chip

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: dbvogt on July 18, 2009, 07:34:06 PM

This is one of a number of drawings I did in Coreldraw 12 and exported to DXF. I can tell if the lines are closed in Coreldraw but don't know how this is done in Autocad.

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: BobsShop on July 18, 2009, 10:30:39 PM

HI db

Loaded your DXF into AutoCadLt 2008.  Your arcs are a series of straight lines instead of arcs.   Try this.

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: RICH on July 18, 2009, 10:56:16 PM

dbvoght,
I think LazyCam is intrepreting the arc's as straight lines because they are not true arc's but rather a spline which
has 4 equaly control points, one at each end of the arc and two between. Some of the straight lines extend beyond
the arc's. I know nothing about Coreldraw but do suggest you dump it and purchase a $30 CAD program as you will have other problems later on because of a paint program.
Sorry to sound a little harsh, but best advice I can give you.

PS: I checked it in 4 different versions of two CAD programs and they all told me the same thing.
Maybe you can try something different in Corel and see if the import is better. For a high level understanding on the DXF importing take a look at the DXF Appendix in the LazyTurn manual which is located in Members Doc's.

RICH

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: Sam on July 19, 2009, 03:45:38 AM

This is a typical problem with Corel that pops up here every so often. Here's a couple links to read....

http://www.machsupport.com/forum/index.php/topic,9153.0.html
http://www.machsupport.com/forum/index.php/topic,7132.0.html

Title: Re: Lazy Cam doesn't create true arcs - makes straight lines
Post by: ger21 on July 19, 2009, 08:59:42 AM

You might want to try the Dxf Tool, which will give you real arcs, and not splines. While the splines appear correct, they're very difficult to work with. I redrew it in AutoCAD.

http://www.candcnc.com/DXFTOOLDetails.htm