ZBrushCentral

Best way to make an alpha

ZBrush Usage Questions
#1

I am making stencils using Photoshop. I know to make it grayscale, but does it matter of my solid shapes are black or white? Also, should I save it as a layer with no background, or a flattened image? What file type should it be? Right now I have a grayscale image, 300 DPI, 2048x2048 px. Any tips on the best way to make alphas for ZBrush would be greatly appreciated.

Thank you.

#2

My tips:

  1. Make sure it has square aspect ratio

  2. Flatten. Zbrush will only see the flattened image anyways, no need to increase file size.

3)Black= Negative space, White = Elevation, Grey=something in between. You can easily invert the image in ZB though for reverse effects.

5)Make sure to make it high enough resolution to support the size you want to draw (and render) it at.

  1. From personal experience, applying a Light gradient blur effect can help smooth the edge transition, which otherwise can be a little “jaggy” in Zbrush. I prefer to do this on the image level, rather than relying on the “blur” control in the alpha palette, as when working at print(high) resolution, this can place a bit of a burden on Zbrush, and sometimes risk a crash.
#3

My problem is that my alphas are showing up in ZBrush inverted, so when I apply the alpha as a stencil and then perform an extract, the revers of what I want gets extracted. Even when I tell it to invert it in the stencil panel, it still does the same thing.

#4

Try inverting it in the alpha palette before you convert it to a stencil? I am not currently in a position where I can test your issue.

#5

OK I tried an experiment with just a simple cube, and a simple square alpha that I made. When I do an extract with that, it merely copies and expands the whole cube, and ignores the stencil. Is it possible to make an extraction using a stencil? After I activate a stencil and move it into place, do I need to turn it into a mask or take another step? Thanks.

#6

This seems to be the solution. Thank you for your help!

#7

I’m still having troubles with this. Making a file in Photoshop and turning that into and Alpha, then turning that into a stencil is not the problem. Once I have placed my stencil over a tool, that’s where everything stops and I can’t use the alpha to extract a subtool. I must be missing a specific step. Once I place the stencil, can I just press Extract, or do I need to do something with the masking palette? Because what I am doing now is not working.

Thanks for your help.

#8

Stencils don’t have anything to do with extracting directly. Extractions are made from a mask, from hidden geometry, or from a layer.

You can bypass the stencil, and apply the alpha directly as a mask. Select a “Drag Rect” stroke type for the Standard brush, select the Alpha you want, hold down CTRL, then drag out the mask shape where you want on the model.

Alternately, you could derive the mask from a texture. (You’ll need UVs for this). Apply a texture or generate one from polypaint, and explore the “mask by” commands in the Masking palette. Use the stencil to paint the texture.

There are probably about a half dozen other variations you could also use to do this…Zbrush provides a wealth of options for working conversions between masks, alphas, and textures.

#9

don’t forget that you can make alphas right inside zbrush by adding 2.5d brushstrokes, primitives, geometry right to the canvas and then doing a alphagrabdoc.

#10

I tried painting a mask through the stencil and it did not work, it masked right over the tool regardless of the stencil.

For a second there, I had hope it would be that easy!

#11

I like to make alphas by laying things out in 2.5D mode (Pixols) and then using “grabdoc” on the alpha pallet to make an alpha.