In PS just make sure that the Offset values are half your image map dimensions. So for an image 256 x 400 pixels (width x height) put 128 in the Horizontal figure and 200 in the Vertical. Then make sure 'Wrap Around' is checked and click OK. Now, using the Clone tool get rid of the horizontal and vertical lines that will have appeared in the middle of your image, being careful not to change the pixels along the edges (otherwise it won't tile well). That's it. You can test it in PS by selecting the whole image (Ctrl+A) then Edit>Define Pattern. Got to File>New for a new image and make it much large than your tile, select all, Edit>Fill>Contents>Use Pattern. In Carrara 3 (if you are using it) you could use the UVMapping feature in the Vertex Modeler to output a template that you could use - but of course there would be no need to tile an image if you were doing this. Otherwise make sure you use an appropriate mapping mode in the Shader tree and test the number of tiles to get the best result. HTH Mark