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Cannot resize document before export and cannot get my alpha to work in Photoshop

ZBrush Usage Questions
#1

Hi there,

I am trying to render an image of my sculpture out of Zbrush with an alpha channel so that I can drop it onto a background image in Photoshop, but am running into 2 problems:


  1. Before I export the document and alpha from ZBrush, I cannot seem to increase their resolution from the default 960 x 720 pixols. I have tried going into the Document menu, and typing “2000” into the Width slider (the Height slider automatically updates to “1500”), and then grabbing an alpha and exporting the document. But the alpha and exported document are always 960 x 720. I have also tried pressing the “Resize” button, but this seems to take the 960 x 720 document and simply scale it up, turning every pixel into a big chunky block, rather than creating a new higher resolution document from the tool. How do I increase the resolution?
  2. When I lay the exported alpha on top of the exported Document in Photoshop, there does not seem to be a blend mode that actually cuts out the Zbrush sculpture and surrounds it with an alpha channel so that I can then lay it atop any background image I want. Instead every blend mode surrounds the sculpture with opaque blackness. How exactly can I use the alpha to composite my exported document?
Please help – I am going nuts!

Thanks,

Dave

#2

1 ) Remember that your model, once dropped to the canvas, is made of pixols. So just as when you resize an image in photoshop, you will also get artifacts when you resize a document in ZBrush. Set your desired document size before you begin creating your picture in ZBrush.

2 ) In Photoshop paste the exported alpha onto the color image. With the alpha layer selected use Select > Color Range with fuzziness at 0. Click a point containing absolute black and then OK. Select the color layer and delete using the selection you just created.

#3

in the document panel after you set the dimensions you have to hit RESIZE.

turn off PRO if you don’t want it to scale the document proportionally.

To get an alpha channel to use for masking in PS you simply do an alpha>grabDoc.

Then in PS you’ll need to adjust the levels.

You can also make your entire object white and your background black and then just do a texture>grabDoc or simply export out the Document.

Hope that helps.

#4

Thanks a million, guys

Problems solved!