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Courtesy of Meindbender |
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Displacement Types - On the fly, Pretesselated and Vector
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1D displacement map (middle) applied to a simple plane. Height Maps contain displacement information only in the vertical direction
3D Vector displacement map (middle) applied to the same plane. Vector displacement can specify direction in all three axis |
Maxwell Render has three methods of displacement:
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Example of very fine displacement using On the Fly displacement method |
Displacement parameters
Map
Loads a displacement texture to access the displacement parameters. Maxwell Render can use 8, 16 or 32-bit grayscale displacement maps. It is recommended to use at least a 16-bit displacement image to create a smooth displacement, because 8-bit images may not contain enough gray levels (they contain only 256 height levels), so you may end seeing a stair-stepping effect if using 8-bit maps. 8-bit maps may be enough for displacements that do not require smooth transitions between grey levels, and additionally Maxwell Render’s texture interpolation helps to render even 8-bit images smoothly.
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Vector displacement always requires 32bit maps |
Subdivision
Subdivision defines surface accuracy, ability and response to detail, independent of texture resolution. Before the surface is displaced, it is recursively subdivided, and this parameter is the measure of that subdivision level of the mesh: the higher the Subdivision value, the more accurate the result. However the more the mesh is subdivided during render time, the more it will influence the render time (in addition to Height which has the most negative impact on render time), or in the case of vector displacement it will use more RAM. Subdivision has no negative effect on render time when using the Pretesselated method.
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Because the On the Fly and Pretesselated methods have a completely different approach to subdividing the geometry, the final subdivision in the render could be slightly different, but for most displacements, in general terms: On the Fly subdivision = Pretesselated + 1 subdivision |
Adaptive
The Adaptive option locks the subdivision value to the given texture detail (at half pixel accuracy), which has the advantage of always creating the most detailed displacement that a given texture can provide. The user does not have to guess what the maximum subdivision value should be for that texture, or worry about exceeding it (which would increase render times but would not necessarily increase image detail - see example above). The adaptive mode should be used with care, because using a very large-resolution texture to represent some simple detail will result in unnecessarily long render times.
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Adaptive mode can add substantially to the render time, especially with big displacement textures. This mode should be used mainly to “test” your displacement textures first to see how much detail can be obtained from a given texture size. Then you can switch Adaptive off and manually raise the Subdivision value until a level of detail close to Adaptive mode has reached. |
Subdivision Method
Define the method used to subdivide the mesh between Flat and Catmull/Loop. The Flat method subdivides the mesh, maintaining the original shape (a subdivided cube keeps looking like a sharp cube), while the Catmull/Loop method smooths the mesh while it it subdivides it, providing a more organic look (a subdivided cube appears like as round).
Offset
This parameter allows you to specify which gray level in the texture should represent zero displacement. It is important that you set this parameter correctly, based on the way the displacement map was created. For example, some displacement maps may use 50% gray as zero displacement (darker shades than 50% in the texture will create cavities, lighter than 50% will raise the geometry). In this case, you should set the Offset parameter to 0.5 to get a proper displacement. If your displacement map uses black to represent zero displacement, set Offset to 0.
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This parameter is not |
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relevant when using Vector displacement. |
Smoothing
Similar to the object’s normal smoothing angle setting, this parameter controls whether the displaced surface should render smoothly (continuous shading) or in a faceted way. It is generally suggested you leave this setting to “on”, unless you aim to render very sharp, detailed displacements such as sharp corners. Please note that the object's smoothing angle will still override the smoothing used for the object’s base mesh faces, so if the object’s smoothing angle is set to Flat (faceted rendering of the object ), and the smoothing parameter is set to “on” in the displacement parameters, a smooth displacement surface will be rendered over a faceted base mesh surface.
UV Interpolation
Allows you to choose the interpolation of the UV coordinates for the new geometry, choosing from:
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Height Map Properties (for 1D displacement only)
Height
This parameter sets the maximum distance displaced. It tells the engine how much real geometric height you want to displace on your base mesh. This value needs to be greater or less than zero for displacement to appear. The white areas of your texture will be raised to the height value you set. Displacement height can be set in percentages or in absolute units:
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Vector 3D Properties (for 3D displacement only)
Transform
Indicates if the displacement information coded in the vector file corresponds to displacement in Object, Tangent or World space at each point. It's derived from the settings used in the vector displacement map creation.
RGB Mapping
Indicates the order of the axis information associated to the R, G and B channels of the map. It's derived from the axis system with which the vector displacement map was created.
Scale
This parameter is used to control the overall size of the displacement (in X,Y,Z). Replaces the Height parameter (present on 1D displacement) because here the height values are derived from the map pixel values. It usually takes values lower than 1.0 on vector displacement maps saved in absolute tangent mode.
Preset
The different modeling and sculpting applications in the industry used to create vector displacement maps offer different settings of the previous parameters to compile the displacement information into the vector map. Given the huge amount of export map possibilities, Maxwell offers a collection of presets adjusted to the export methods of the main modeling tools that automatically set the fields with the corresponding options:
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