3D Toolkit: VDMs and Alphas

VDMs and Alphas
VDMs and Alphas are two different brush components that can be used to rapidly add details and patterns to the surface of a model in a manner that is simple and optimized, both techniques different from one another in outcome and functionality whilst being somewhat comparable in broad strokes. 

Alphas influence how a brush disperses when its stroke is painted across the model. This is good for rapidly creating repeating or randomised patterns, such as scales, pores in skin, bricks on walls or rust on metal.
VDMs - Vector Displacement Meshes - can be used like stamps to alter the geometry of a mesh, imprinting a form on to it that can be much more detailed. As such, VDMs can be used to rapidly imprint eyes, facial features, horns and other such detailed components onto a model. A library of VDMs can be built around this functionality: for example, multiple eyes, ears and noses could be created for use in character models. Planning and creating such a library would then expedite future character models made.

To create an Alpha, I downloaded a free rust texture off of the texture and photograph website "Pexels". In photoshop, I then created a square canvas and imported the image, setting it to greyscale and sharpening the contrast between the black and white. I did this because Alpha maps only read black and white, and use the difference between these tones to compute the depth between them. With the image in greyscale I then created a layer mask, filling the canvas in with black and using this to create a circular selection of the greyscale image. I made sure that none of this selection touched any of the edges of the canvas, as this would create a sharp edge when the alpha was painted on to the model.
With the alpha complete, I exported the greyscale selection as a .tiff file, which is the file type that Zbrush uses to read alphas. With this, I could import this rust alpha in to Zbrush and use it to influence a model.

To test out the rust alpha, I imported my previously made alien model and used the alpha on the metal pieces of the alien's legs, adding rusty detail across their forms. 

To create a VDM, I first created a flat plane with high topology, which I then sculpted a pattern on to. This pattern would then become the VDM. To create a VDM based off this pattern, I went into the "Brush" menu and selected "Create Multi Alpha Brush". I then went back to the alien model and used this to stamp the VDM pattern on to the robe of the alien, imprinting the detail of the pattern on to the mesh. 

As such, I have used VDMS and Alphas to add detail to the alien model I made for the previous submission, and feel I have gained an introductory understanding for as to how these functions can be used in the 3D pipeline.