1.How good is RoGR at milling 3d stuff for example, a human face?

2.How is the DIY 36" Z-motion kit coming along?

Did you see where Brainchild digitized his face and milled it into a pumpkin? Just an example of which you should be aware. Not quite what you're asking though.

Just wanted to kinda point out a slight reminder on it, I figure you already realized this...but just in case.

It's not a true 3D mill. It's 2.5D. Which sounds weird at first, but for something like a face, that's all the more it is anyway. It basically is unable to do the undercuts...so the details at the top must always be at most the size of the cut prior to it. Which if you think of it from the router...that bit is straight and is going to stay straight...so unless you add a 4th axis (and I think a 5th is needed as well...) to get the piece to rotate so the router can make those other cuts as well, it can't be 3D.



But for 2.5D I see no reason why the Rogr/micRo couldn't handle it as well or better than any other 3 axis mill.

Note also Brain is constantly dropping mouth-watering hints regarding adding axes to make RoGR truly 3D as well as other tantalizing things. But patience is required for all things Lumenlab.

It is a true 3D mill as it is. It has 3 axes (thank you brainchild, I'm no longer calling them "axises"), which makes it capable of 3D cuts.

2D = The machine can only move the X and Y axes (X is one dimension, Y is the second, hence "2"D)
Plasma, water jet, and laser machines are "2D"*. They can move around in the X and Y axes and ALL they can do is cut through the material. You cannot make "steps" with a plasma cutter.

3D = The machine can move 3 axes: X, Y, and Z.

From what I've seen, 2.5 mostly refers to the CAM software, not the mill.

2.5D = The CAM software can handle X and Y movements, and to a limited extent, Z. 2.5D works just like 2D, but it's possible to command the machine to cut the 2D paths at different depths. You can make "steps" with 2.5D CAM software, but you cannot make smooth slopes and contours (like a human face, or a hemisphere).

I'm afraid my descriptions are pretty bad, maybe these pics will help...
Here's something cut in 2D...
Click to view attachment
There is only one depth of cut: all the way through.
Photo from here: http://www.torchmate.com/photo_of_month.htm

This is a 2.5D piece...
Click to view attachment
Although it's fairly detailed it's still 2.5D. It looks like there are 2 distinct sets of cuts on this piece: all the way through and approximately 80% through. It would be impossible to make this on a plasma cutter.
Render from here: http://www.graphcam.co.nz/Products.shtml

Here's a 3D milled object...
Click to view attachment
Although there are no undercuts it is considered a 3D piece because the machine used to make it had to move all 3 axis at once.
Photo from here: http://www.extralite.com/Products/E-Bones%20qrc.htm

Any more than 3 axes is usually referred by how many axes there are. Adding a lathe to your mill will make it a "4 axis" machine.
Here's a very cool video of a 5 axis machine: http://www.youtube.com/watch?v=QsmiIeAkE-o (note: other than the techno and the sounds of the machine, there isn't any audio on the video, so mute it if you want.)

* It's probably possible to do etching on these machines which might quality as 2.5D in the most technical sense.

I've been under the impression that 3D referred to the ability of an integrated package (software and hardware) to perform undercutting to some degree (if a cutter has the proper shape - like a ball end - it can undercut to some extent) and required smooth integration of motion along all three axes such that complex curves could be milled in x, y, & z. I have to applaud Hirudin's little explanation above. Well done. Clear and concise. Yeah, the RoGR is indeed a 3D machine. It'd be pretty crippled at only 2D.

Thanks for the video links. I've always loved watching coolant flooding over stuff.

If a machine can cut a hemisphere (or semisphere); defined as "any section of a sphere less than 180° around", then the machine is capable of moving 3 axes simultaneously and is thereby "3d". "Undercut" is "4D" (and is practicably, "5D").