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Displacement Amount | rendDispl, rendDisplEnbl – Specifies a displacement strength multiplier.

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Gradient 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 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.
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 of the fluid's Surface channel. The texture is also sampled at the projection point.  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 point is shifted by the texture color, interpreted as a 3D vector. This displacement mode is intended to be used with the Phoenix Ocean Texture but can be used with any other vector displacement texture.

• • 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 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. Can be combined with the Phoenix Grid Texture, with its Channel set to Velocity, to produce render-time gridless advection.  For more information, see the Advection Displacement example below.

Vertical Fade Level | rendDisplFade, rendDisplVertFade – How high above the Ocean Level the displacement will stop having effect. This option is available only in Ocean Mesh and Cap Mesh mode and it is needed for ocean simulations where you have liquid flying or splashing high above the ocean surface, so that the ocean displacement will affect only the calm ocean surface, but will not displace the liquid flying high above the ocean, or you would be able to see small pieces of liquid move up and down as they fly due to the ocean waves displacement. Above the Vertical Fade Level there will be no displacement at all, and below it the displacement will be strongest near the Ocean Level and will gradually be reduced moving up from the ocean surface. This parameter is a percentage of the grid height, just as the Ocean Level option.

Fade Above Velocity | rendDisplVelFade, rendDisplVelFadeEnbl – If the fluid velocity (in voxels/sec) in a voxel is higher than this value, there will be no displacement at all. When the velocity is lower than this value, the higher the velocity, the weaker the displacement will be. This allows you to suppress displacement for the fast moving parts of the fluid where the displacement would visibly disturb the motion in an unnatural manner, and thus you can have only the still ocean surface displaced with waves. This option requires the Grid Velocity channel to be exported to the simulation cache files from the Output rollout.

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Use Fade Volume | usefadeobj – When enabled, allows you to specify a geometry object as a fade volume. There will be no displacement inside this object and outside it the displacement will be gradually reduced at a distance specified by the Volume Fadeout Distance parameter.

Set Selected Object as Fade Volume - When a polygon mesh and a Phoenix Simulator are selected, the selected object will be used as the displacement Fade Volume of the Simulator. 

Fade Volume | usefadeobj, fadeobj –  There will be no displacement inside this geometry object, and outside it the displacement will be gradually reduced at a distance specified by the Volume Fadeout Distance parameter. This is useful if you have a geometry such as a sea vessel moving in high displaced waves, or a static geometry such as a beach into which the fluid is splashing. In these cases, you can use these geometries as fade volumes and use small Fadeout Distance around them, so the displaced liquid mesh and the objects would match precisely - otherwise the displacement may pull away the liquid from such geometries or force the liquid to penetrate them.

Volume Fadeout Distance | displgeomfade – Specifies the distance in world units around the object where the displacement will fade out.

Example: Advection Displacement

Example: Advection Displacement with a Monochrome Map