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Fog and GDI
Fog and GDI
admin, added 2006-07-27 13:42:03 UTC 30,438 views  Rating:
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Some of you know about Fog and use it to blend your scenes and help with depth effects. Few of you will know about the GDI and GSI slots in the lighting menu. Both can be used to greatly enhance lighting effects and can be used for more dramatic effects. The possibilities are endless. I decided to make this little tutorial to show one way they can be used. Experiment! It's the best part of Zbrush...everyday brings some new wonder.

click for larger version

What you will need for this tutorial:
* Anh Nguyen's head model which can be downloaded with some other great models when you download a ZBrush demo. Or... a ZBrush created alpha of a head (or anything ya like really).
* My Image: Fog_and_GDI_tute.zip
* Your creative, experimental, Zaddicted self
To Prepare:

You might find it easier to create a "temp" folder within the Zbrush folders perhaps within the ZExportImport folder and name it Temp or whatever ya like and unzip Anh's and my files there. So much easier when everything is in one place!

Let's get started:

1. Start Zbrush!

2. Create adocumentthat is twice the size you wish your final picture to be..up to 4096x4096. I set mine to
2048x2048. Now click theAAHalfbutton. This gives you an anti-aliased final pic in the size you desire.





3. Note: If you already have a head alpha skip ahead to step 11.Load Anh's head into thetool menuand Subdivide a few times to smooth it out (or as much as your ram will let you do this comfortably). TurnQuick
off. This will also help smooth it's appearance.

4. Now click on smallest color patch just above the color swatch and make sure it's 0,0,0 Black then click theSwitch Colorbutton and make sure that the larger swatch is pure white. This will make your life so much easier as we go along.



5. ClickSwitch coloragain, taking a look at the swatch to make sure black is selected, and hitCtrl-fto fill the current layer. (Make sure you don't have any textures loaded first or they will fill the canvas.)

6. ClickSwitch colorand make sure white is up and draw the head onto the canvas. It may look as though it's half in and half out of the canvas. This is ok, I positioned mine to hide the neck edges into the canvas but you can use theMove Gyrotool to move it in or out however ya like. I also centered it a bit on the canvas.



7. Go to tool menu and select theMRGBZGrabbertool (click switch now button if you were in edit mode). Now click drag on the canvas from about the center of the head til the "rectangle" more than covers the head. It's cool if ya have never used the grabber tool before and it takes ya a time or two to get the hang of it, we have all been there before. when ya got it where ya like it release the mouse button.

You should now see both a newly created alpha and a texture of your canvas grab. You can export out the texture if ya like (I have another tutorial planned that will be using our newly created texture and alpha so you can savethem both to save some steps later on or just experiment on your own....whatever floats your boat).



8. Load up the 3 textures I included in the zip file so that they are handy, then turn textures off.

9. Switchto black andctrl-fthe layer.

10. Go to theLayer menuandcreate a new layerandctrl-fthat as well. You should now have two layers filled with black.

11. Switchback to white color, make sure your head alpha is still loaded, load thesimple brushand select thedrag stroke, withzintensityset at 100 draw your alpha to the canvas.



12. Now we can experiment a bit here. Try different settings and redraw your alpha to the canvas....find one that suits you......play with these things:

Zintensity,Focal Shift, in the Alpha menu you haveMaxto turn on and off,RFyou can set to fade off the edges, and thealpha curveto play with.Note: you can at any time switch to black to ctrl-f the canvas then back to white to continue experimenting if you run out of room.