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Author: Kemp Sparky
* Poser 5-7
* Image Editor
de'cal [dee k'l] (plural de'cals) n. Picture for transfer: a picture or design on specially treated paper that allows it to be transferred to a surface such as glass, wood, or metal. Decaling in poser: To place a high resolution image on a model by scaling and positioning using UV coordinates. This tutorial will show you how to overlay 'decals' over existing textures using masks and material room nodes. I will show you my progress as I map an emblem onto a tabard.
The decal, in my case, is an emblem. At first, I tried to put the emblem directly onto the texture. I found that the effect was dissatisfactory. The emblem, on a fairly high resolution texture came out blurry and with very little detail. Not only this, but I was mucking up my hard drive with copies of a texture that were unnecessary, and causing problems during rendering with high memory usage, due to the size of the textures needed for the detail I wanted. So, I resorted to this technique instead. The mask is just like a transparency map. 'Mask' all the areas of the image that you do not want to show up after rendering with black, all other areas will be white. You can also use shades of grey to create translucent, or blended areas. Fig. 1 shows my decal and mask.
Go into the material room, and apply your decal as the diffuse map. Not quite what you were hoping for, is it? Fig. 2 shows the result in my case.
Now, how to scale the decal? In the advanced tab of the Material room, you see the node titled 'Image_Map_#' (where '#' is a number), and which displays a thumbnail of your decal when you hit the eye icon in the upper right corner. There are two fields that are called 'U_Scale' and 'V_Scale, ' both are set at 1.0 by default. These dials run from 0.0-1.0 0.0=0%, and 1=100%. One thing of note, is that the pixel size of your image has no bearing on its relative size in the material room, which allows you some freedom with your images' sizes (the mask need not be the same pixel size as your decal, only the same shape; if you want to make your decal image larger or smaller to add more detail or lower memory usage respectively, you need to make no changes in the material room as long as the image retains its shape). The U axis controls the horizontal and V the vertical (Fig. 3). I scaled mine to 0.08, or 8% of its original size. Fig. 4 shows us my progress so far.
At this point, it's nice if you want a patterned cloth, but I just want one emblem. Notice that the node shows Image_Mapped: Tiled. That would explain the tiling effect, wouldn't it? Change 'Tiled' to 'None.' You should now see a single decal, huddled in the lower left corner of the white space of the texture preview. If I were to render this now, I would have nothing more than a white tabard, since the emblem is not over the place where the UV mapping of the tabard is. You will now need to utilize the fields that say 'U_Offset' and 'V_Offset.' Once again, the U axis runs from left to right, and V from bottom to top. But how do you know where the decal needs to be? The preview doesn't show you. Will you have to tweak the coordinates and render, tweak and render over and again? No. Just below 'Image_Mapped' it says 'Background, ' click the plug icon to the right of it, and select New Node > 2D Textures > image_map. Now, navigate to either a texture template for the object to which you are applying the decal, or the texture that you want to show under the decal later, if applicable. Fig. 5 shows what my material looks like at this point. Now, play with the offset dials until you think your decal appears to be in the right place. I set mine to 0.858, 0.845. As you can see from Fig. 6, it appears to be in the right place.
It's starting to look good, but it still has that green box around it. Well, that's what the mask is for. We start by opening up a blender node. Click on the plug next to 'Diffuse_Color, ' where our decal is currently plugged in, and select New Node > Math > blender. The blender node has three fields: Input_1, Input_2, and Blending. Change the value next to 'Blending' (0.5 by default) to 1.0. Plug your decal into 'Input_2, ' disconnect your background from the decal node, and plug the background texture into 'Input_1.' Copy and paste your decal node, plug the new decal into the 'Blending' field of the blender. Change the 'Image_Source' of this node to your mask, and change the background color of this node to pure black, or RGB 0, 0, 0. Fig. 7 shows the final product.
One thing to note, is that decals will not overlap UV seams.
Now that you have learned this technique, you can apply it in all manner of ways. To make certain areas of a body part look more detailed, to create transparencies in clothing, to add tattoos to characters, and more.