ZBrushCentral

Dynmesh subtract.. fail. And a related CTRL-SHIFT click question

ZBrush Usage Questions
#1

Part 1 of my question

  1. Make 3Dcube
  2. T > edit, check
  3. Dynamesh with blur at 0
  4. Duplicate 1st cube
  5. Set duplicate 2nd cube sub attribute to negative in subtools menu, from two circle icons filled to two circle icons half filled
  6. Used deform on 2nd cube to make it fit inside 1st cube, and stretched to stick out of both sides
  7. Selected original cube
  8. Merge Down
  9. Result - Both cubes now a single object added together.

And I got the darn thing to work once, but haven’t been able to repeat it.

Sorry if I seem to be posting lots of simple questions, I keep thinking I have it, and then something seemingly so simple twists me in knots… I’ve seen other people with similar problems but the solutions for them don’t seem to work for me… thought I would try and exactly show my steps to identify where I went wrong.

Part 2 of my question
In a video (Military Assets with Joseph Drust, Creating a “Picatinny” rail Part 1 at 2:27) trying to show how to do this (dynamesh subtract), the instructor teacher shows different tools, a flattened cube/sheet was one, and he said “Ctrl-Shift click” and an object disappears… I never could for the life of me get anything to happen with just a click. Even dragging it does nothing to any object like in the video…

Thanks for any help… little stressed out, have to mail my Wacom Cintiq Companion back because they used sub-standard power jacks and now it won’t charge unless you nurse it along every few minutes…

#2

In R6, supposedly in most situations the subtracting mesh has to have a lower polycount than the target mesh.

I’ll give you a couple tips though.

  1. Make use of the “Group as Negative Sub” function in the Polygroups menu to avoid all the rigamarole with the boolean icons in the subtool menu. Just make sure your objects are different polygroups, and group the negative mesh as a sub after you merge them with the aid of visibility gestures.

  2. An easier way to achieve the duplicative subtraction you’re trying to do in your example is:

a) Get a polycube, turn on dynamesh

b) enter move mode, click on the side of the cube to draw a transpose line.

c) Ctrl-Alt click drag on the middle circle of the transpose line to duplicate the object within the same subtool as a negative mesh, which will auto mask the original cube. Optionally hold down Shift to constrain movement along an axis. Position as desired. Switch to scale mode to scale it down.

d) Dynamesh with the “groups” button in the dynamesh menu switched ON. This works for me, and circumvents all the other requirements for some reason. Dynamesh by ctrl-dragging in empty canvas space once to clear the mask, then a second time to initiate the remesh.

For your second question, commit these visibility functions to muscle memory as soon as possible, and use them in conjunction with polygroups. It will make your life much easier:

http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/mesh-visibility/

#3

You seem to have omitted a step in your process. Make PolyMesh3D has to be performed before you can get to the Dynamesh part in the Geometry panel…

#4

Yeah, I forgot to put that step in, I did do it, and once I dynameshed, then I duplicated it so it was also dynameshed.

So followed your example and it subtracted correctly… going to follow the link you provided…

Thanks, I think it was the dynamesh groups toggle that was a big part of my problem…

8 )

#5

Thanks, I think it was the dynamesh groups toggle that was a big part of my problem…

That really only applies in this specific scenario. In other situations, Groups will make for unwanted effects. Only turn it on if you specifically want the effect it offers, unless you’re doing that specific duplicate subtraction thing.

#6

Great so now I am back at square one of why it didn’t work…

#7

Probably because of the very first thing I told you in my original post.

#8

My question to you is. “Are you using ZBrush 4R6 P2?”

#9

4R6 yes, not sure about “P2.”

#10

Spyndel, I will tell you what I DO want. I want ZBrush to work like the instructors show in their tutorials, both here in ZClassroom and in tutorials from Digital Tutors. That’s all i want. I don’t want there to be 50 different specific reasons why something won’t work like they show me i a tutorial because I am int he third wednesday of the odd month of the year, and so forth.

That’s all i ask, and when something doesn’t work that way, and i ask here why not, and am told a way to get it to work, and then when I apply that and it doesn’t work, then I get told “well it only works if the clock hand is in the 4th quadrant, and that solution only works on certain days in certain condiions”… I get a little frustrated.

But hey, if I didn’t like the program so much, I wouldn’t come back and ask for more help.

So please, bring it on! Heh heh… eventually I’ll figure out all the exceptions…

Thanks to everyone!

Now I need to figure out if I have this P2 thing.

#11

ZPlugins>AutoUpdate

#12

Spyndel, I will tell you what I DO want. I want ZBrush to work like the instructors show in their tutorials, both here in ZClassroom and in tutorials from Digital Tutors. That’s all i want. I don’t want there to be 50 different specific reasons why something won’t work like they show me i a tutorial because I am int he third wednesday of the odd month of the year, and so forth.

Assuming the instruction was accurate, it probably did work that way for the version of Zbrush they were using. Zbrush changes in significant ways with each program update, and yet older documentation and tutorial material remains. In this case, the dynamesh behavior changed significantly from r5 to r6, and allows you to do some more complex things, but is also a bit less intuitive in some situations, specifically this very duplicate subtraction scenario.

Zbrush development has always been highly fluid, and development sometimes outpaces documentation. You either learn to accept that, or stick with tools that aren’t quite as on the cutting edge.

That said, it’s entirely possible your technique was faulty in some fashion in your original post, and the instructions you were following were accurate. I simply wasn’t willing to check it step by step, so I gave you one of the most common problems, and easier methods for doing what you were trying to. I’m afraid I have little patience for finicky subtool merging procedure.

That’s all i ask, and when something doesn’t work that way, and i ask here why not, and am told a way to get it to work, and then when I apply that and it doesn’t work, then I get told “well it only works if the clock hand is in the 4th quadrant, and that solution only works on certain days in certain condiions”… I get a little frustrated.

It can be frustrating to learn a tool as complex as Zbrush all at once. It can seem overwhelming at first. The people that answer your questions here didn’t learn it in a single week. We became familiar with it over the course of months, and years.

Complaining, however, is wasted here. These boards are largely attended by volunteers. If you have a bug report, a usability issue, or a feature request, you should address that to Pixologic directly. They may very well not see it here. The only thing complaining here will accomplish is to risk alienating the people you’ve been getting a lot of help from over the past week.

#13

Just to make sure you have a clear understanding of the process, the subtractive mesh must be of a lower poly count than the target mesh (two duplicate objects are the same poly count), and when merging down, the target active dynamesh subtool must be selected (in other words, the target mesh must be above the subtractive mesh, and merged down on top of the negative mesh).

http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/creating-meshes/dynamesh/with-subtools/

It’s a bit fussy. Which was why I gave you the easier method for subtracting with a duplicate. I don’t know why using the groups function in that specific duplicate scenario works…it could be a bug as far as I know. It used to work that way in r5 without any special consideration.

It’s generally much easier to perform subtractions with meshinserts.

#14

Awesome, thanks for the in-depth explanation… one final question for now… how do I make sure the polycount is lower for the subtractive mesh… especially when I copy the original and scale/size the copy? Or as in most cases I insert identical tools, how do I lower the polycount on an identical tool, yet still retain the shape/proportions I wanted?

Thanks again tons, lots of valuable advice!

#15

It’s rare that you ever have to worry about the polycount thing. Most “cutting” objects tend to be lower poly than the target mesh. It’s an issue here because you are duplicating an object, but I gave you a better way to do that in any event. Easiest thing to do is just subdivide the target object another time to make sure it’s higher poly. You’re going to remesh it in a moment anyway.

Remember, you can subract with Insert Mesh brushes by holding down ALT as you draw them into an object. Any object you’re currently working with can be made into a new mesh insert brush with the “MakeInsertMesh” command in the brush menu. Likewise, any object can be cloned as a negative mesh by Ctrl-alt draging on it in Transpose mode. You can assign any object as a dynamesh sub in the polygroups menu, but that is still subject to the rules on merging subtools.