ZBrushCentral

how to insert mesh at an exact predetermined size and location [Answered]

ZBrush Usage Questions
#1

Greetings,

I think the boolean subtraction option (by pressing alt when inserting) when using the new insertmesh brush is great.

However, is it possible to insert a custom mesh automatically at a predetermined size and location without having to drag it out and then resize and move into place?

Typically I would like to do this:

  1. create a sphere

  2. create a cube subtool at a size and location on the sphere where I would like to boolean subtract it from the sphere

  3. then I would clone the cube

  4. then select the insertmesh brush and select the cube cutter object and press “alt” and click on the sphere and have it appear at the predetermined size and placement

  5. flicking control twice would then subtract the cube from the dynamesh sphere

Is this at all possible? It would make the insertmesh brush much more friendlier and efficient to use; rather than now you have to click and resize and move it multiple times to get it to where you want it.

Thanks for any solutions.

#2

Well, in most cases it’s the same amount of work to position and size a cube before inserting it, as it is to do so afterwards, isn’t it?

However, there are cases where you would like to be able to merge a subtool down that has been specifically placed, perhaps even in an outside program, and use that to cut with.

Unfortunately, there is currently no way to force tag a mesh in place as negative, which is what you would need for this.

However, there are some tricks.

If you duplicate a mesh with the transpose Move mode, by ctrl-alt dragging on the middle circle, the duplicate you create will be negative. So you you can merge a subtool down, move it away on an axis by Shift-moving the middle circle, which constrains movement, then move the negative duplicate back into place along the same path.

If you merge down a subtool that you have positioned exactly as you wish, and ctrl -alt click , but dont drag it, it will be negatively duplicated almost in place with minimal (but not zero) offset. Since the transpose duplicate function automasks the original tool, you can immediately invert the mask, and either mask or hide the target mesh temporarily, to move the original non-negative mesh you duped out of position.

All a bit fidgety, yes. But at one point we didn’t have subtools, and then when we did, it was a juggling act to merge and split them. The point is, Im confident you can look forward to improvements in usability for this virgin functionality over time.

#3

To add to what Scott has already said (thanks Scott :slight_smile: ) you may find this useful:

  1. Append the cube to your sphere and position how you want.
  2. Select top subtool and press Tool>SubTool>Merge Down.
  3. Turn on polyframes (Shift+F).
  4. Turn on Move mode and Ctrl+click on the cube. This will mask everything else.
  5. Draw out the Actionline and position so you can see clearly. You can move off the model if you want so the Actionline shows clearly against the background.
  6. Ctrl+Alt+click in the center of the center white ring. If you click in the center this will duplicate the mesh with no (or very little) offset.
  7. Clear the mask by Ctrl+click+dragging the background.
  8. Press Tool>Geometry>Dynamesh.

The duplicated cube will subtract from the sphere. The original cube will still be there (probably rather holey) but will be a different polygroup to the sphere. To get rid of it:

  1. Turn on Edit Draw mode and Shift+Ctrl+click the sphere. The original cube is hidden.
  2. Press Tool>Geometry>Del Hidden.
#4

Ive been trying and trying to get this to work for me and it just wont. I just cant get zbrush to draw out a negative mesh. its always just a duplicate, but never a negative one.

I must be missing something, but I just cant see it.

#5

Do you mean not at all, ever? So following these steps you do NOt get negative meshes:

  1. Load the DefaultDynaWax64.ZPR project from Lightbox.
  2. From the Brush palette select the InsertCylinder brush.
  3. Hold Alt and draw out the cylinders (there’ll be two as symmetry will be on).
  4. Turn on polyframes (Shift+F).

The cylinders should be white, showing they are negative. Holding Ctrl and click+dragging the background twice should do the Dynamesh boolean.

#6

no if I use an insert tool to insert a negative mesh that works fine. but using this method to duplicate a poly group as a negative mesh, I just get another identical poly group, it never comes up as a white copy.

Im finding it very frustrating.

#7

Try this:

  1. Load the DefaultDynaWax64.ZPR project from Lightbox.
  2. Turn on polyframes (Shift+F).
  3. Turn off Symmetry. Turn on MOVE mode and draw out the actionline.
  4. Hold Ctrl + Alt and click+drag on the white circle in the middle of the actionline.

A white duplicate of the sphere should be created.

#8

OMG Thank you so much! I’ve been trying to do this since ZBrush 4 came out! :laughing:
This little tutorial really helped me! However, I hope in a future version of zBrush there will be a button in the subtools palette that says “Subtract Down” or something like that, to make this process easier! :+1:
Thank you again Marcus! :wink: