3D Modeling with Bitmaps

[Joe Crumley]

Could some one please explain why bitmap modeling isn't used more for 3D carving. I'm aware of only acouple of instances where bitmaps are used for carving. The now famious whiz kid "Carvewright" works totaly from bmp's.

Also there is Artcam and Enroute that uses bmp for background textures. Another program is "Photo V Carve" supported by Vetric. It seems to be limited to shallow rendering. In this process the darker parts of the images are deepest areas carved. So my question is, what are the drawbacks.

It seems much easier to scan and cut rather than building a mesh model.

[ger21]

The drawback is that it's usually not as simple as scan and cut. Extensive editing of the bitmap may be necessary to get the results you're looking for. And this is beyond the abilities of most people. The colors or levels of greyscale of an image don't necessarily translate into the correct height or depth of the cuts needed to make. The reason that Photo Vcarve is limited to shallow cutting, is that it's designed for a specific application, cutting photos.

Also, ArtCAM's strength is using vectors, not bitmaps. And it's $7000+

There's plenty of software available to cut bitmaps, if your so inclined. Mach3 will even do it.

If you want to try a package that makes extensive use of greyscale bitmaps, check out Bryce. And a series of books called "Real world Bryce" that will give you techniques for bitmap modelling that you'd never imagine.

[Joe Crumley]

Gerry,

Thank you very much for the reply. I'm very encouraged. I'm also very appreciative of your technical expertise and your excellent writing ability. I know when you post, the information will be good workable and reasonable hints.

I'm now running a Ez CNC which is powered by Mach 3. Perhaps I should give Mach a look see how the bmp generator works.

I full well understand the potential difficulty of converting colors to gray scale and maintaining the proper depth. There is a demo in Photo V Carve which points out this problem. And that program does an excellent job of correcting it.

Since I'm fairly adept at gray scale manupilation in PhotoShop, it seems reasonable for me to proceed with that. Although I would like to save the 7K it cost for ArtCam, it's not the money alone. I've tried the Artcam demo on creating 3D files. It was difficult for me. This isn't a program to be used every once in a while, if time is important.

Thanks again for your assistance. I will do the investigation you suggest and keep you up to date.

Joe
www.normansignco.com

[pointcloud]

http://forums.cgsociety.org/forumdisplay.php?f=149

You might find something here...

+rhino and rhinoArt will do...

Gerry don't you use rhino?

[Joe Crumley]

Thanks for posting.

I believe the Rhino as many of the 3D mesh programs applications are vector generated. While it's a great technical program it falls short in freehand applications.

If I may speak for Gerry, yes he is more than acquainted with Rhino. It's one of the old standard.

J
www.normansignco.com

[ger21]

I know my way around Rhino a bit, but don't use it. I've played with it occasionally since the very first betas of Rhino 1. The main programs I use are AutoCAD and Lightwave, but I can find my way around most CAD programs and modellers.

[pointcloud]

Yea they are all close...

[kiwichris]

If you're just doing simple 2.5d stuff, any drawing program should do shouldn't it? Or have I missed something here? We're talking about taking images and creating 2.5d 'reliefs' of them in wood/plastic ?

I did a quick play with convering an image of a rose to grayscale in the gimp, then used a quick'n'dirty home brew script to convert to Gcode, the result didn't really look like a rose, but it proved the idea could work. I just needed a better sorce image, or a better way of manipulating it I suppose.

I imagine one of the edge-finding type filters in would give you somethign workable...

I'll find the big of plastic I 'rosed' and take a pic...

Cheers, Me.

[Joe Crumley]

Chris,

What I'm looking to do is full 3D images from bitmaps.

I've been directed, by one of our group, to Mach 3.

There are aparently other software programs which also come into play. It's a search to find the best one. I'm looking for advice from those who have experience.

[davidmb]

Hi Joe,

Take a look at MeshCam, there are a few versions now including an art version, but I remember that the very first version can use bitmaps to generate a height field. It generates the gcode as output.

[kiwichris]

Originally Posted by Joe Crumley Chris, What I'm looking to do is full 3D images from bitmaps.

? I'm confused, a bitmap is a 2.5d format effectively.. You have X and Y, and a Z 'value' which is the colour/shade.

How then are you going to create a full 3d model from a bitmap?

[pointcloud]

It is not 3d but it will be more than just lines.

The colors would be the depths or heights..
I'll get an example from my other comp...