In this Tutorial I'll go over the creation of a Tool to create Seamless Displacement Maps in Zbrush.
Quick Breakdown:
1. Create Plane3D and Make PolyMesh 3D
2. Duplicate, using Deformation Panel, Offset in X -200. Duplicate Original Again and Offset in X 200, then Merge all together and Weld. Do ctrl+w to Polygroup all. Now you have a Strip of 3 Plane 3D Meshes welded together.
3. Repeat the Process from step 2 except Offset in Y -200 and Y 200. You Should have a 3x3 Grid Now.
4. Time to setup some Polygroups. One group is the Center Most Grid. Second will be a 3 Polygon border around the Center. Third group will be the rest of the Grid.
5. Now Hide the outer most Polygroup and in Geometry Panel Click Divide. As you can see you've only subdivided the 2 inner most Polygroups. Repeat this Process until your around 6 Million Points.
6. Your almost there to start creating Seamless Textures. Now Change your document resolution to 2048x2048. Zoom out to see the whole Canvas. Do ctrl+N to clear the canvas and Drag in your new panel you created be sure to use Shift to align the Panel. Isolate center most grid and click frame, in visibility panel click ShowPt to unhide the other Polygroups. On the Draw Polyframe Button deselect Line so you just see the Polygroup Colors. Pick the Brushes you want to use and change the Wrapmode to 1 in the Brush>Curve Menu. Now start drawing with no seams.
Check out the Video Below for a more in Depth run through of the Technique
You can go to my Gumroad Page also to Download the .Ztl file and get started right away.
https://gumroad.com/glenn1993