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the4thseal
01-17-2012, 09:33 PM
I would like to take pictures of an object with a known reference. using cad get measurements. using the photo i would like to overlay the cad drawings, then using cad file create g-code. How do i do this.

I have Auto cad and rhino. I think this should be easy, how wrong am i?

macona
01-17-2012, 09:52 PM
Not easy at all. There are ways take an image and trace but accuracy cab ne pretty terrible. CorelDraw can do this. And then you need to output it in a vector format and take that into cad and fix it.

I have found it is usually easier to redraw the part in cad.

the4thseal
01-17-2012, 10:31 PM
What i would like to do is bring in the photo and trace over. Down and dirty kind of work. Corel draw can do this? Do you know which corel product, or just corel draw?

DFMiller
01-18-2012, 12:53 AM
I know Solidworks can use a Jpeg as a background to draw to.
Dave

macona
01-18-2012, 12:58 AM
That might be out of his price range!

Whatever the latest version of corel is should do it.

Some of the art orientated CAM packages also do this stuff for signs and the like. ArtCam is one, Bobcad has an art packare called BobArt that might do it as well.

Black Forest
01-18-2012, 01:01 AM
Alibre will also allow you to bring in a picture and trace over the picture.

the4thseal
01-18-2012, 01:53 AM
i have solid works.i have never thought of using it that way. The surprise is Corel draw. i would not have thought of that.

macona
01-18-2012, 01:58 AM
i have solid works.i have never thought of using it that way. The surprise is Corel draw. i would not have thought of that.

Thats what we would use at TechShop to run the laser cutter. It needed vectors for cutting. Initially we had an Epilog and it had a print driver that handled it. Then we got one of the chinese machines and you needed to export a DXF into the control software. So I messed around with CD quite a bit and got decent results.

Stepside
01-18-2012, 09:39 AM
Take a photo and use View>Background Bitmap and trace the part. Then measure some key points and scale the drawing to fit. Key points would be shaft diameters, distances between two features ect. If they are tiny parts and you have an optical comparator, then enlarge the parts to fill the comparator screen and take a photo of just the screen. This will allow you to have a large bitmap to trace and then you can scale later. If no comarator then get as large an image as you can with your camera. What you want is the greatest number of pixtels of the object so you can make the largest bitmap rectangle.
Quuestions?
Pete

the4thseal
01-18-2012, 10:18 AM
that makes sense. So i should convert my pictures to bitmaps?

Stepside
01-18-2012, 11:12 AM
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
01-18-2012, 09:28 PM
Im new to ALL of this, but im using Simplycam, try it for free and buy it for a few bucks....

the4thseal
01-18-2012, 09:31 PM
I have that issue. I thought i new that from somewhere. Off to read it again.
You are using simplycam for this?

dneufell
01-19-2012, 05:51 PM
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
01-22-2012, 10:48 AM
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
01-22-2012, 03:41 PM
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
01-22-2012, 09:31 PM
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
01-30-2012, 08:15 PM
Draftsight - A freeeby - has a menu item to "Insert Reference Image" and then you can trace it.

legendboy
01-30-2012, 09:24 PM
would this be like doing a litho?

the4thseal
01-31-2012, 02:22 AM
litho? I must be thinking of something something else.

legendboy
01-31-2012, 09:22 AM
yea i was thinking of something else

http://www.edingcnc.com/upload/files/Lithopane_PhotoVcarve.pdf

Gadget
04-05-2012, 09:09 AM
Mechsoft has a program that can capture an image from a part using a video camera and generate GCode to recreate the part. It ties in with Mach to do this and is fairly reasonable. If you have the original part this may be a good option.
Dan

Toolguy
04-05-2012, 09:19 AM
Bobcad v24 Bobart has a feature of being able to make a program off a picture. I don't know how it works, but the salesman told me they had it.

legendboy
04-05-2012, 11:00 AM
I have done this many times to get competitors extrusion drawings however it is pretty much impossible to get it exact. Even scanning profiles on our copier doesn't give the correct "perspective" of the picture

I insert the jpeg and scale it to the proper size and draw 2d over top of the picture with autocad.

It seems things go out of proportion, especially nearing the edges of the picture.

JEZX
04-05-2012, 06:28 PM
whats the picture look like ? maybe send it to some one with programs to get it to the g code . id give it a try for you if you want .

Gadget
04-06-2012, 09:53 AM
Mechsoft has a program that can capture an image from a part using a video camera and generate GCode to recreate the part. It ties in with Mach to do this and is fairly reasonable. If you have the original part this may be a good option.
Dan
Guys, I got the name of the company wrong on the cnc scanner. It's made by Tormach and can be found here http://www.tormach.com/store/index.php?app=ecom&ns=catshow&ref=CNC_Scanner

You can scan an object with a cheap video scanner on your CNC table and it will basically reverse engineer it and leave you with the code needed to reproduce the part.
Dan

MaxHeadRoom
04-06-2012, 10:06 AM
Here's an old link from Torchmate.
http://torchmate.com/technical_support/corel_draw_functions/scanning_an_image_in_coreldraw_into_vector_format/
Max.

Steve Seebold
04-10-2012, 01:32 AM
There is a company called Arbor Image that makes a program called Cutting Shop that changes a rastor file to a vector file that can be saved as a .dxf file then machined.

I use it occasionally. If you don't use it a lot, you'll get rusty and forget how to do it. It's kind of complicated.

When bought mine in about 2005 and it was about $1,200.00 per seat then.