Open Photoshop and create a new document. Set image size to 4096x4096 pixels @ 72 pixels per inch & change to RGB colour mode.
Next click Filter>Alien Skin Eye Candy 5:Textures>Brick wall
You can load presets from the Settings panel, or create a new texture using the Basic panel.
For this example we need to set the brick dimensions correctly, so we will use the Basic panel. The Brick Pattern drop down list, will give the most commonly used brick stack types. Running gives a 50% offset as shown.
The Seamless Tile check box should always be activated, unless a specific non tiling texture is required.
Next we need to do some calculations to set the brick dimensions correctly for the resolution of the texture.
Standard UK brick size including motar is:- A=215mm x B=115mm x C=75mm.
215mm to 75mm gives a ratio of 1 : 2.866666 -> This is the number we need to use for the Aspect Ratio.
The brick height in pixels is dependant on the texture resolution. A simple formula can be applied to work this out.
V = x resolution of texture map.
W = required number of bricks across texture.
X = brickheight in pixels.
Y = result of first calculation.
Z = aspect ratio.
In this example below, V 4096 / W 4 = Y 1024 / Z 2.87 = X 356.79
Colour variation ammount will help to give whole brick tonal variations, as well as increasing the 'blotchy' appearance of the bricks.
As you can see this texture would repeat too much when tiled, as it only has four bricks across the x resolution.
So for normal applications I'd have at least 64 bricks across the x resolution, with 128 and more for very large areas of wall.
Using the same formula as before, 64 bricks would give a brick height in pixels of 22.299. 128 bricks would need a pixel height of 11.149
The aspect ratio would be constant throughout all calculations.
Now that we have set everything as required, we can click OK and wait for the plug-in to create the image data.
You may need to tweak the other settings depending on what type of texture you're making.
Once this has loaded, add a new layer and name it 'Bump'.
Then run the plug-in again, click Filter>Alien Skin Eye Candy 5:Textures>Brick wall.
This time we can keep all the dimensions as before, but we need to change the brick A & mortar B colours to grey and black.
Using a brick colour of 128,128,128 will give the most tonal range, which in turn when used as a bump will give height variation across the texture. Tweak the colour variation ammount C to best suit the texture you're creating.
In the zoomed in example below, I've used a value of 41,41,41 for the mortar, which helps to keep some of the detail.
Click ok to apply the Brick to the image.
Next duplicate the 'Bump' layer and rename it as 'Specular'.
Please do not just invert a bump map and hope that it will be acceptable as a specular/reflectivity map. Specular/reflectivity maps require all aspects of the image to be considered, adjusted & modified for the specific application of the map.
It's bad practice to rely on just an inverted bump map, don't do it. A bump map can and should be used as the starting point for a specular map.
For specific use with Maxwell, we need to create a selection set for the mortar, to aid in creation of the roughness/specular map.
Create a new layer called 'mortar selection'.
Then open the brick plug-in again Filter>Alien Skin Eye Candy 5:Textures>Brick wall.
This time we need to use pure black for the bricks A, with no colour variation C and a pure colour for the mortar B. RGB 0,255,0 in this case.
This allows us to use the green Channel to select the mortar. All other settings need to be kept as previous. Press ok to confirm settings.
Select the new layer we've just made, in the Layers panel and then open the Channels panel. Hold CTRL and left click the Green channel to select the mortar.
We need to use the selection set to invert the value for the mortar, so hide the selection layer, then select the Specular Layer and press CTRL+I to invert from black to white.
Now we need to control the levels of the specular map. Make sure you deselect any selection and with the specular layer selected, add a levels adjustment layer.
Lightwave uses the inverse to Maxwell specific roughness maps, for specularity/reflectivity. If a Specular BSDF layer is used in Maxwell, then the inverse of this map would be used as a weight map for that layer, as per Lightwave.
All that's left is to save out each Layer as a individual .PNG image file, named accordingly. Colour, bump, Specular etc.
Grout/mortar weight/clip maps.
If a weight map is required for the mortar, use the method described in step 7, but use pure white instead of green for the mortar colour. Then save out this layer as a .PNG named accordingly. Jump back to step 7.
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Tim Ellis 2010 - firstname.lastname@example.org