Info on advanced toolpaths for wood carving?

[lesd]

First off: This is my first post here !

I'm about 1/2 way done building a 6' X 4' gantry based CNC rig for both plasma and wood work.
The question I've been pondering is the concept of tool path generation for the purpose of reproducing wood carvings, ala reliefs in 2 1/2 D.

In the software I've seen so far, the tool path generated seems to be rather simple. A raster, spiral, etc.
I'm wondering if there is any research in making toolpaths that follow edges and curves in such a way to minimize the stair stepping and other 'CNC' looking artifacts usually expected from doing a carving style piece.

For example, a relief of a daisy, the tool path should follow the edges of the petals and not make a raster pattern.

Is there any information on these types of tool path generators, that follow dominant edges in an object ?

This is a great forum, I look forward to participating more as my machine gets finished!

-Les

[High Seas]

Les - Welcome aboard! There are literally ahundreds of ways to get where you want. I was looking for a similar approachand did a short review of a few programs. Have you checked:
http://www.cnczone.com/modules.php?n...rticle&artid=2
yet. There might be some help there. SOme of those programs have demo/timelimt freebe downloads - you can run many on you pc without having the machine n th lop. Good opportunity to check out the software while finishing up the hardware.

BTW - some pics as you go along would be cool!
Jim

[lesd]

Thanks for the reply Jim!

I just checked that thread you posted. I'm still not sure I can get what I need, however. Those products seem to handle the vectorization very well, but it looks like they still generate raster type tool paths in the end.
The 'Topo' caught my attention, as the contour lines of a Topo map are similar to the tool paths I'd like to get, but it didn't do that.

Perhaps an example of something to make tool paths for: A relief of a snake in a S pattern, no undercuts, the cross section of the snake is shaped like a half circle. A standard raster toolpath would move the tool left to right and after each pass would move down a little ( in Y ) until the job is done. The Z would be going up and down as the tool path 'hits' where the snake is.
What I'm after is something that follows the back of the snake in the S shaped path, and keeps making deeper cuts as the tool needs to reach the edge of the snake.
A silly example, but an example, none the less.
Another example would be a several flowers in relief. The petals of the flowers are curved a little in the z direction ( not just a flat cut out ) . The ideal toolpath would cut around each petal making a nice edge to it. The surface of the petal might be handled by a raster pattern, or a spiral. But the edge would be 'stair step free' because the tool did a trace around it in this example.


This may be something that doesn't exist, I don't know.
Maybe it's would make a good thesis project for a grad student

Thanks again for the help. I'm definitely going to post pictures of my gantry. I've made it bridge style out of welded aluminum, to try to keep it light and rigid.

-Les

[ger21]

I think you're looking for something like MasterCAM, but be prepared to spend at least $2000, probably a bit more. I think most of the highend metalworking software can do what you want, but usually your in the several thousand dollar range.

Checkout http://www.mastercamart.com/Machining/Default.asp , and look at the spiral to boundary toolpath. still a raster type path, but closer to what your looking for.

[turmite]

Les I don't know if this is what you are wanting or not but I whipped it up to at least see. If so I did this with bobcad v17.

Uh well I tried but the file size is too large and I can't do any photo manulipation right now. The tool path lays along the length of the s curved snake....is that what you want?
Mike

[lesd]

Mike,
That might be it ( if it follows the S shape) , do they have a name for the type of tool path method it used ?Can Bobcad import a DXF mesh that would be the 2 1/2 D relief ?
-Les

Les I don't know if this is what you are wanting or not but I whipped it up to at least see. If so I did this with bobcad v17.

Uh well I tried but the file size is too large and I can't do any photo manulipation right now. The tool path lays along the length of the s curved snake....is that what you want?
Mike

[turmite]

Les send me your email to Ihatespamnonna01@earthlink.net and I will email you the full size jpg. I recently had to have a new motherboard put in my pc and the tech that did it took me for a cleaning. I now have all my files spread all over my computer it is slow as death and many of them are missing. Anyway take out the I hate spam in the email address and sen me yor address and I will get the screen shot back to you.

I don't know to the dxf mesh, but if you are going to get bobcad to do the cams part you might as well draw in it as well. This is not an endorsement of Bobcad/cam nor is it critical but if you plan on doing this for very long think long and hard about spending a little more money for your cam software. The toolpath can be named either ruled or zigzag and that depends on how you set up your toolpath selection and direction. You can also carve outside and inside.

I carve gunstocks on a 4th axis and am currently writting the can program to run the lentgh as you are wanting. My problem is that a snake is basically two identical sides and the arc is the z axis to form the toopath. The gunstock has several some very wide and some very narrow. I have to stitch several programs together and do lots of editing to get a workable program. I know that their new version 19 can import a surface from stl or iges and the cam section can write directly from the surface. It is probably what you are looking for. I am looking for something more than that and just don't have the money to do the direction I need to go. $4 -5K is about about what I will have to spend to get what I want.

I use Rhino for my modeling and I want a program that will take the native Rhino 3dm file and use it. I also want 4th axis.

I just though of another program that might work for you. Easy to use too. Meshcam. I think but am not sure you can select the direction of the toolpath.........but not aht I think agian it will still be only in straight lines llike you aren't wanting. Take a look anyway. Robert has a forum here on the zone.

Mike

[HomeCNC]

Les:

Is this what you are looking for? It was done in ArtCam Pro

[lesd]

Jeff, that looks like it!
Does Artcam make those tool paths or does it just do the 3d object ?
I seem to recall that artcam only did the simple 'spiral' 3D path method.
What do they call that 3D path style ?
-Les

[HomeCNC]

ArtCam will do both 3D object and tool path. The machining stragity used above is the "Offset" method. I chose the outline of the griffin and told the tool path to just do the inside area and to start at the outside and move to the center.

Below I chose the oval cavity and told the tool path to "Offset" from the outside to the inside just as above.

[lesd]

I did some checking, and it seems that these tool paths aren't available when doing the model from an image height map. Is it true that you have to model with artcam vectors ( non image based ) to get the tool paths to follow the 'topo map / water line ' contours ?
-Les

[ger21]

Les, make sure you check out the price of ArtCAM. I believe its $7000+