ZBrushCentral

3D printing with ZBrush, "subtools" and technology...

ZBrush Usage Questions
#1

Sculptris user here. I wonder whether any ZBrush users are able to “resolve” a “debate” about how advanced ZBrush is, in terms of 3D printing.

The “debate” has got caught on whether you are able to print a “ZTool” with multiple “subtools”. Some of us are claiming that, before the .stl file is exported, the ZTool is allowed to have multiple subtools, but, more critically to the debate, that these two or more subtools are allowed to overlap! Others are claiming that if two or more subtools overlap, faults would be caused.

Who is right here?

If two different subtools did overlap to some extent, so that they shared some volume or enclosed some of the same space, would this generate an error? Both of the subtools would be “watertight” in-and-of themselves… but if those subtools were to overlap, would this be an issue?

I believe the argument is coming about because this group is not sure whether two subtools with an overlap in their volumes means that the model as a whole would be “manifold” or “non-manifold”.

Maybe some answers to this will prove useful to others, who are also trying to work this out. I hope I got the ZBrush terminology right. Sorry if not. (I’m a Sculptris user, and considering saving to buy ZBrush so I can collaborate with friends who I think mainly use Blender. Maybe I should stick to Sculptris, but again I find myself wishing there was a demo version of ZBrush available… even if it were a few versions back. Haha! But that’s not what this post is about!)

Thanks for any and all advice / answers. :slight_smile:

#2

The manifold error isn’t created by Zbrush if you have two manifold meshes interpenetrating. This will throw an error depending on the software used by the 3D printer. Some software will overcome this error and generate a new mesh on the fly by reading the surface volume of the mesh and generating a new mesh accordingly. Magics (http://software.materialise.com/magics) will do this and then kick out a proper file type for, basically anything. Granted, Magics is +$8,000 a seat.

You can test your theory rather simply by sending a mesh to a 3D printer to have it tested. Just make a box, and put another box inside of it sticking out a bit. See if their software will interpret that as an error or have no problems reading it.

Some software will read the volume of all manifold objects, it doesn’t care about interpenetration, but it doesn’t understand the interpenetration when calculating the total volume. It simply reads each volume and gives you the total volume. This doesn’t cause an error in the printing process, but it can cause an error in the cost estimate as the software will give you the total of both volumes (if you use the 2 cube test) rather than the volume 1 + volume 2 - volume 3 (interpenetration volume).

I hope that makes sense.

#3

Like was mentioned it’s based on the software running the 3d printer. I have never had a problem with multiple separate pieces overlapping to create one physical piece. The program will warn me of the overlap and ask if want to print anyway. However it’s easier to decimate the subtools and join them into one object and then send it to the printer. Again it will let me know that the model has intersecting faces but it doesn’t cause issues in the print.

Printing services may or may not use these restrictions, they will vary. Some will use restrictions as a general guide line even if their hardware/software can bypass them.

#4

^^^^ I’ve found this to be the case as well.

After exporting the .stl from Zbrush, I also just open it with Netfabb basic (free) and use the automatic repair functions (if necessary).

http://www.netfabb.com/basic.php