cad from pictures for G-code.

[Stepside]

If using Rhino, use a .jpeg as a source for your bitmap. The bitmap is like putting an object behind glass and then tracing what you see. It has no control except visual control.
Use colored layers to see what you have traced. Then using curves, circles ect to trace the bitmap. Make sure you don't delete your bitmap until done tracing. Adjust curves/lines to make sure they have the correct angle and as close as possible curvature. When you think it is good, then measure (analyze) important parts of your drawing so you can scale it properly.

You can then use the lines/curves to generate the G-code. You could "ordinate dimension" the drawing and handwrite the code or you could use a CAM product to write the code. See the Fall 2011 issue of Digital Machinist magazine.

[daveo]

Im new to ALL of this, but im using Simplycam, try it for free and buy it for a few bucks....

[the4thseal]

I have that issue. I thought i new that from somewhere. Off to read it again.
You are using simplycam for this?

[dneufell]

I was just reading a thread here or on Practical Machinist and at the bottom of a guys post was a sig line. I do not know anything about it but it looks intresting

http://www.picengrave.com

[Mcgyver]

i The surprise is Corel draw. i would not have thought of that.

The program is Corel Trace, bundled with corel draw. Makes vectors out of pixels. Really handy for logo's etc.

[Stepside]

The difference between the different programs, Coreltrace, Rhinoceros ect is the actual accuracy you can obtain. So the question is does it just have to look good or does it have to fit something? If it has to fit, will the software have the ability to meet the tolerance required.

The manufacturing method also plays a part in the choice. There is a great difference between a Plasma Arc, a wood router and a CNC milling machine. There is also a great difference in accuracy between the different size and quality of the output devices.

[the4thseal]

I am looking at this as a process and just another too in the tool box. Sometimes you just have to be close. I would like to be close and use it as a method of capturing geometry that defies regular means of capturing. When tight tolerances are required it would be one step in a process.

[kf2qd]

Draftsight - A freeeby - has a menu item to "Insert Reference Image" and then you can trace it.

[legendboy]

would this be like doing a litho?

[the4thseal]

litho? I must be thinking of something something else.