simple import, extrusion and print

General MeshCAM Art Questions

simple import, extrusion and print

Postby pepper » Sat Oct 03, 2015 1:45 pm

Seems like a decent program for its price, but it doesn't really take into consideration actual end users. For instance, the sample files included in the program are odd, purple and red and whatnot multi-colored files. Who as a graphic designer would even prepare such a thing? A more realistic demand on the program is to properly and elegantly extrude

http://www.3dcadbrowser.com/th/1/9/9987.jpg

But it seems to have difficulty with this.

1. When importing a .jpeg, the blacks set to z- protrude beneath the white of the image and the white of the background. Makes sense. However, when importing a .png file with an alpha layer, the alpha layer imports as a white background. Blacks set to z- end up like a jpg. Black set to z+ create this convex misshapen thing.

2. Does the program have a File > New setting? I'm forced to > close every time? The re-import icon should re-import alongside previously laid images rather than obliterate them.

3. The file will not import very large files. Anything over 3000 pixels delivers an error message.

4. The "Shape Relief" option allows fine-tuning of various shapes -- BUT ONLY if the image is one of those weird purple and red whatnot images that as I indicated above no graphic designer would ever really produce. And since the program only works with swaths of colors, attempting to deal with various shades of gray either produces odd results or takes much, much fiddling, which is my point ... it doesn't really consider the needs of real end users.

5. Other than that .. for a circa 1991 WIndows program, this has potential, but I'm wondering if my money isn't better spent elsewhere.
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Re: simple import, extrusion and print

Postby Randy » Sat Oct 03, 2015 3:02 pm

Hi pepper, and welcome to the forum. When importing a bitmap, MeshCAM creates a heightmap from the equivalent grayscale brightness of each pixel, 0 to 255 range. MeshCAM does machine the whole rectangular bitmap, but there has been some speculation among users (myself included) that it would be useful to sense "transparent" pixels around the edge and confine the machining to the actual colored pixels.

If you are expecting MeshCAM to convert the goblet image into a bas-relief type of surface, it can't. There is no existing software that can do that as far as I know. Check the recent thread viewtopic.php?f=6&t=15547 for some links as to research and experimentation in that regard. It turns out to be a very hard nut to crack and noone has done it really successfully yet. http://orca.cf.ac.uk/42170/ describes what is probably the best effort so far.

MeshCAM isn't a graphics editing program, any more than it is a CAD or solid modeling program. MeshCAM creates toolpaths from an existing input file. Just as MeshCAM only imports one STL file at a time, it works with one bitmap at a time. Any image compositing or overlaying must be done in your graphics program before importing to MeshCAM.

The example images that are circus-colored are inputs for MeshCAM's Art functionality, where the solid-colored areas are really a mask for embossing/debossing the defined areas to create the 3D shape. Look in the Help for an introduction of how Art works. Many programs import bitmaps to create simple heightmaps--that is how you do lithophanes for example ( viewtopic.php?f=4&t=446&p=957 ) but MeshCAM's Art is a distinct functionality from importing a bitmap for automatic heightmap generation. The two have different purposes and workflows.

In Version 6 Build 27 Robert increased the maximum image size to 90000 pixels.

There are many programs that work from bitmap input, and many that work from STL input. You'll need to evaluate the various programs versus your needs and make your own decision. But I'd encourage you to read through MeshCAM's Help section and also browse the extensive information here on the board to give it a fair evaluation. I've been using MC since early betas (see my sig) and am very happy with its capabilities.
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
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