This page provides general information about the Displacement sub-section of the Rendering rollout of Phoenix FD.

Overview

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Displacement is a technique intended to add detail to the simulation during the rendering. The idea of the Phoenix displacement is similar to the usual geometry displacement: a texture is sampled, and the corresponding point on the mesh of the fluid volume or surface is shifted in a direction at a distance determined by the texture. You can plug both any V-Ray and regular , Maya or Phoenix texture maps, as well as the PhoenixFD Ocean Texture. 
You can use the Phoenix FD Simulator's Mesh Preview option to check how the attached displacement map is affecting the surface when rendering a Liquid simulationsurface when Mode is set to Mesh, Ocean Mesh or Cap Mesh.

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Type | rendDispltSurf – Specifies the displacement technique.

Gradient drivenGradient driven – Requires a monochrome (black and white) texture map. The point is shifted toward the field's gradient by the texture brightness. The displacement amount is the texture's brightness at each point. Each point of the fluid is shifted along the gradient of the Surface channel. This means that each point in space could have a different displacement direction. This method is suitable for smoke and fire. The Gradient of a channel is the direction in which the value increases. In the case of a plume of smoke, the center is the densest area, and a Gradient-driven Noise displacement map will appear as bumps all over the smoke surface. 
Surface driven – Requires a monochrome (black and white) texture map. The point is shifted by the texture brightness toward
Surface driven – Requires a monochrome texture map. The displacement amount is the texture's brightness at each point. Each point of the fluid is shifted along the normal of the point's projection on the isosurface . The of the fluid's Surface channel. The texture is also sampled at the projection point. The Surface driven method is slower than Gradient driven but   Unlike the Gradient driven displacement, this ensures that all points above of below the fluid surface will be displaced in the same direction, and so displacing fire/smoke simulations produces better results that are more similar to displaced solid geometry surfaces. However, the Surface driven method is slower than Gradient driven.
Vector – Requires a colored vector texture map (with negative and positive values). The  The point is shifted by the texture color, interpreted as a 3D vector.

• If Mode is set to Mesh, Ocean Mesh or Cap Mesh, then it requires a texture in the format used for V-Ray Tangent Vector displacement, where X and Y of the texture are 0.5-based, and the Z direction is 0.0-based. This

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• means that if you use a texture where the Red and Blue colors are gray and the Green color is black, it will produce no displacement; brighter color than these will move the fluid points along the positive axes, and darker and negative colors will displace the fluid point along the negative axes. A texture in such a format is the Phoenix Ocean Texture in Vector Mode.
• If Mode is other than the mesh modes, Vector displacement requires a texture which is 0.0-based, so black color means no displacement, brighter colors shift the fluid points towards the positive axes and negative colors - along the negative axes. Such a texture is the Phoenix Grid Texture with its Channel set to Velocity.

Advection – Requires a colored 0.0-based vector texture map (with negative and positive values). A very similar method to Vector, but does not produce grainy structures for fire and smoke. It requires Can be combined with the the Phoenix Grid Texture | PhoenixFDTexture, with the Grid Texture's its Channel set to Velocity, to produce render-time gridless advection.   For more information, see the Advection Displacement example below.

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