Graphics Pad for freehand carving with CNC router

[foamcutter]

Hi,
I just had this idea of using a graphics pad like a Suma graphics or Wacum tablet as a freehand control for carving with a CNC router. I hope this is the right place for this post.
The idea is where ever you ran the stylis the router would follow just like drawing in CAD. The amount of pressure you placed on the stylis would determine the depth of the cut within parameters set, and when you raised the stylis off the pad the router would raise off the work and move with you to the next place to carve. My question is How Do I Do This and Is This even possible? This could open up many really cool ways to carve one off carvings without going thru the g-code process. What ya think out there am I nuts or just a little off center? Ron

[joecnc2006]

without haveing a expensive router then the diy will not be fast enought to follow you, what i would do is just get a software to convert sketches to gcode. and the darker the line the deeper the cut.

[KissSys]

I have a old summagraphics compatible tablet that I plan on using to make a g-code generator. It has four buttons which can be used for selecting points to follow and telling the Z-axis to go up and down. My machine would follow a pen in XY unless your a very fast drawer. Z axis might lag a little. I don't think I'm artsy enough to be productive with a live cutter, besides I like to delete and redo alot

Steve

[foamcutter]

KissSys,
How are you converting you tablet to be a g-code generator. I have an old Summasketch plus tablet with both a puck or a stylis. I also have a Wacom intuos with wireless stylis. I do a lot of graphics work on photo restoration and I can set the photoshop software so that the more pressure I put on the stylis the more opaque the color becomes or the wider the line becomes, etc. The stylis has 256 steps of pressure, I would like to convert that to Z travel so that say I wanted to carve a rose bud I could increase the pressure as I traced over a pattern and the router would follow in all three axis, the z according to the pressure I used. There would be subtle differences you could create with pressure on the stylis that you could not not any other way I think. Yes I understand I would need to not out run the speed of the router. Actually though when I move faster in working in graphics than the program can work, it will continue to do what I want, there is just a short time lag or delay. I think the technique would come to you as you worked with a live cutter, my problem is how do I get the tablet to tell the router what to do? Thanks to all who have input so far. Ron

[ger21]

Originally Posted by joe2000che what i would do is just get a software to convert sketches to gcode. and the darker the line the deeper the cut.

I doubt any such software exists.

[ger21]

Originally Posted by foamcutter Hi, I just had this idea of using a graphics pad like a Suma graphics or Wacum tablet as a freehand control for carving with a CNC router. I hope this is the right place for this post. The idea is where ever you ran the stylis the router would follow just like drawing in CAD. The amount of pressure you placed on the stylis would determine the depth of the cut within parameters set, and when you raised the stylis off the pad the router would raise off the work and move with you to the next place to carve. My question is How Do I Do This and Is This even possible? This could open up many really cool ways to carve one off carvings without going thru the g-code process. What ya think out there am I nuts or just a little off center? Ron

You'd have to write your own software, that outputs step and direction signals based on your pen movements.

I have an older Wacom ArtZ (I think) that I can draw in AutoCAD, and convert that to G-code. The problem is that AutoCAD doesn't support the tilt angle, or pressure features, so there is no way to get any Z changes in there.

[jphagen]

Dumb question, but why?
You can still draw it. Plus you have the erase or undo for the mistakes?
Draw it, get it right then cut it..

[foamcutter]

ger21,
Thanks for the reply. I have the intuos pad and in Photoshop it translates the pen pressure to either line width or % of opaqueness whichever I have it set to. I have also drawn with the pad in a cad software and it doesn't translate the pressure either. Your probably right about having to write a software myself, my only problem I don't know where to even start writing software like that.

jphagen,
In answer to why? I have at least 2 reasons. #1- I believe with being able to use the pen pressure on a pad connected to a live cutter I can produce some really nice carving with the subtle differences and changes that as far as I know is not possible with just drawing it then convert to g-code and cut. Sort of like the difference in someone playing a piano can create a beautiful sound from a piece of music, unlike a old style player piano that plays the notes but doesn't have the feeling that a real person has. #2 Why not, one never knows where something will lead, maybe even to something great or maybe just to something fun and different, and maybe no where at all. Thanks for your question and input, I find it is always good to ask that one simple little question, WHY?

Anyone out there got any idea how one would create a software to do what I am asking and any idea of how difficult this would be? Thanks to all. Ron

[ger21]

Go to Wacom's website, and under support, they have a developers section which should get you started. One problem I see, is that there would be a bit of a delay from your pen movements to the routers movements.

[ger21]

Another option would be to write a simple "cad" type program that would record pen movements along with depth based on pressure. Then output g-code from that. That would probably be pretty easy. I'm not a programmer, but about 10 years ago, while playing with VB, I wrote a simple program that would let me draw on the screen with the mouse. I recall it was quite simple to do.

[foamcutter]

ger21,
went to wacoms site like you said and read thru all the stuff there. Most all of it went over my head so I guess until they come out with a programming for dummies video this idea will have to be on hold. Thanks for the ideas and suggestions. Ron

[dcarr]

Originally Posted by ger21 I doubt any such software exists.

Actually, it does. I've developed a Virtual Sculpting CAD/CAM software package called VS3D. There is even a discussion forum here at CNCZone for it.

While VS3D is not set up to work with a tablet, it does have numerous tools for performing free-form surface sculpting using the mouse.

In general, I believe that you would be far better off to sculpt the surface first, then cut it. That "undo" capability is extremely important when it comes to carving (sculpting). For example, suppose you wanted to sculpt a relief of a person's face (like on a coin, only larger). If you do it by amplifying your hand movements throuch a DNC device, sooner or later you are going to make a mistake and ruin the piece. Even the most experienced sculptors usually make the initial model in clay. With clay, you can stick material back on the surface (or remove it) as needed.

Now imagine if you could do freeform surface sculpting, but in a virtual (digital) realm. Sort of like using "digital" clay. That is what VS3D is all about. Here is just one example of the type of digital sculpture that can be created:

Once sculpted, there are many machining strategies that can be employed. VS3D, for example, outputs standard G-Code from a variety of different path types (traversal, radial, spiral, peck, contour, etc.). And the true 3-D tool offsets are automatically calculated at each point along the path, utilizing the 3D geometry of the tool bit and the surface being cut.

Various software packages are capable of importing images and converting image brightness into surface height. So for some types of images, that can be very effective and for others it won't work so well. With most of the image conversion software progams, you are stuck with what you get as far as the converted surface goes. But VS3D, for example, allows you to perform additional sculpting on the imported image surface.

Take the case of a photo with a person's face. If you convert the image brightness to surface height, you can sometimes end up with a reasonable low-relief surface that would look good carved into a flat surface. The brighter image areas end up higher and the darker areas lower on the surface. But many people have dark eyebrows. The eyebrows will then be sunken in on the resulting surface because they are darker than the surrounding skin. With a sculpting program like VS3D, you aren't stuck with that situation - you can "lift" the eyrow areas up to the desired surface height.

Here is a VS3D image carving tutorial that shows an image that works well (gray-scales effectively mapped to depth of cut):
VS3D Image embossing/carving tutorial