The idea behind this exercise was to create a block that could be used in a game like Minecraft. The block needed to have seamless textures with overlapping UVs for the sides in order to make the most of the available texture space, a low-resolution bottom because it won’t be seen much, and a high resolution top because that will be seen a lot more.
Here is my in-depth look at what I did and why.
Creating the block.
In order to create a block similar to one that would appear in Minecraft etc, we are going to need a perfect cube. This is done by selecting a cube under the create tab, going to ‘Keyboard entry’ and entering values to the lengths of the sides. I chose the values 20,20,20 to give me a nice equal cube that isn’t too small or large before clicking ‘Create’ to create the specified cube at the world origin. This cube will be ideal because all of the sides are of equal size – this should make unwrapping as easy as possible.
Before we move on, it would be wise to open up the material editor and apply a basic material. By pressing ‘M’ I can open the editor, and from the left I created a standard material and applied it to the cube. For now, it’s just grey but this will be changed later. Along the top of the editor is a button labelled ‘Show shaded material in viewport’ – Clicking this with the material selected will make any textures appear – There isn’t any assigned right now but this will soon change.
Using the modifier tab, I applied the Unwrap UVW modifier to begin unwrapping. The first thing I do is open the UV Editor. Because the cube is a hardly a complex mesh, we can go to the Mapping tab along the top of the editor and click either Flatten, Normal, or Unfold mapping.
Unfold mapping will take the cube and unfold it, keeping everything connected. If we enable the checkerboard pattern, we can see in the viewport that the squares are all equally sized and seamless. Although this is useful in a wide range of scenarios, it’s not what we’re looking for. This leaves Normal and Flatten Mapping as potential candidates. If we choose Normal Mapping, we get a dialogue box asking us what type we want. If we choose box, we get every face of the cube laid out nicely to the left of the editor, all scaled uniformly and not connected to one another. Flatten mapping does the same, taking every face and placing it in the editor, not connected.
We could use either of these. First things first, we need to find which way the faces are rotated. In the viewport, click the top face. This should highlight it in the UV Editor, and show which edges of the other faces are connected to it in blue. The blue should be at the top of those faces – these faces are the sides of the cube. Drag the top face out of the grid, and repeat with the bottom face. Next, we will want to place all of the side faces on top of eachother to make the most of the available texture space – they are all going to be exactly the same so there is no need to take up additional texture space if there isn’t going to be any difference between the faces. This needs to be done as accurately as possible. Next, we will place the top face directly above the side faces, making sure that the bottom edge is touching the top edge of the side faces. This will make creating a seamless texture easier. We will now take these faces and place them into the grid, and scale them as large as they will fit to make the most of the available texture space – allowing the highest resolution textures possible. The bottom of the cube, however, won’t be seen much so there is little reason for it to take up much space. As a result, I scaled it smaller than the rest of the cube and put it in a corner. I then saved the UVW Template and put it over to photoshop.