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SubTool Merge, Subtract & Add on Basic Primitives - Working or Not

ZBrush Usage Questions
#1

It’s been a while since I used Zbrush, but I’m running into a problem and it’s this:
I have a sphere as one object that’s placed at the top level and a cylinder on the level below; they intersect each other. The icons on the visibility level that I’m interested in are, Add (Union), Subtract and Intersection. The icon selected on the top level is add while the icon selected on level two is subtract. The way I interpret this is that if I merge level 1 & 2, I should get a boolean subtraction, but nothing seems to happen other than the levels are merged and a new (union) tool is created. I seem to recall that this worked in an earlier version of Zbrush with these basic primitives, but that doesn’t seem to be the case anymore. Either I’ve misinterpreted how this works or am using the wrong method. The Help file is no help at all and the user guide doesn’t even display these icons when you look at information on SubTools. So the question is, how do I subtract a cylinder from a sphere?

#2

You are missing the most important step. The subtool set for subtract needs to be given the new unique polygroup for doing Boolean subtraction. If you navigate down to the polygroup menu, towards the bottom is a button called “Group as Dynamesh Sub”. Click that, and the new polygroup will be white, depending on the material you are using. Then simply merge down and control/drag on the canvas and the Boolean subtraction will work.

If you go the the Zbrush classroom, you will find a bunch of recent videos by the awesome Joseph Drust. They concern creating military assets, and the first couple of videos explain this workflow in great detail. Super easy to follow, with epic results.

Derek

#3

Thanks Derek I’ll certainly give that a try (already did and I can’t get it to work) and will also check out the videos you recommend. You know, it’s this type of stepping through hoops that is probably the most frustrating thing for new Zbrush users and I’ve always thought that nothing is really as simple and straightforward as it should be eg. having to go to another menus and change you object/s to a Dynamesh sub, then return to another menu to do a merge down, then do a ctrl drag on the canvas to make it happen, it’s just plain crazy. In other ‘normal’ 3D programs Boolean operations are simple and easy to understand whereas in Zbrush they are frequently convoluted never simple and infrequently easily understandable for beginners. This is generally reflected in the documentation that comes with the program, which in my opinion is aimed almost exclusively at those who are familiar with the program. Anyway that’s not your doing and I thank you for your response, which I greatly appreciate.

#4

Make sphere, put cylinder subtool below it and select center icon for subtract, hit Remesh all. Now 3 subtools.

#5

Thanks Doug - that was the first thing I tried, but the end result was too slow and too messy.

#6

Okay I’ve worked it out.

  1. Create a sphere in a new document
  2. Duplicate it to object two - set the object two icon to subtract (object one icon is automatically set to union)
  3. Click on top layer & open Geometry
  4. Click on Dynamesh - change resolution & blur to suite first
    5.Go back to Subtool & click on top level object then choose Merge Down
  5. Hold down Ctrl & drag on the canvas - boolean operation is executed and object two is subtracted from object one.

This does the boolean subtraction

Thanks for the feedback guys.