This means that in order to get a similar tessellation level, using a shading rate value of X would translate in using a micropolygonlength value of sqrt(X): While shading rate was expressed in terms of area, micropolygonlength is (as the name indicates) a length. The micropolygonlength attribute is a successor to the (deprecated) shading rate. The degree of tessellation is driven by the dice micropolygonlength. Primitives are tessellated into micropolygons. However, tessellation will impact the frequency at which displacement is computed (because displacement happens for each vertex of the tessellated mesh). In particular, a coarse tessellation shouldn't affect any texture filtering, or yield blurred patterns. Note that the tessellation will not impact the frequency at which shading occurs (because shading happens at each ray hit). This may happen for NURBS and subdivision surfaces (in order to provide a smooth surface), or for primitives associated with a displacement shader (in order to provide a detailed mesh to displace). In RenderMan, some primitives may get tessellated at run-time. Volumes are used to render participating media with a heterogeneous density such as fog, smoke, or clouds. They can also be used to render viscous fluids directly. Implicit surfaces are another type of specialized primitive, most often used when dealing with fluid simulations generated by a third-party package. However, note that subdivision surfaces inherently have a higher memory cost, and dense subdivision surfaces may be less efficient than the equivalent polygon mesh if the geometry is highly over-detailed.Ĭurves are specialized primitive which excel at rendering long, thin geometry such as hair, fur, or blades of grass. Many polygon meshes can be converted arbitrarily to subdivision surfaces and will immediately gain the benefit of a smooth appearance. Subdivision surfaces generally provide an easier way to produce smooth, curved surfaces with almost no modeling restrictions that are well suited for animation purposes. However, they require a restrictive quadrilateral-only topology that may be demanding to model. NURBS are true curved surfaces, are efficient, and yield very smooth results. However, their efficiency is hard to beat especially when rendering collections of hard objects such as buildings or cities. Polygons are simple and individually lightweight, but detailed models and curved surfaces may require many polygons for acceptable quality, quickly becoming memory-intensive (even with RenderMan's very efficient implementation). Object instancing is fully supported as well. #Renderman shading rate fullRenderMan supports a full range of geometric primitives, including polygons, NURBS, subdivision surfaces, curves, volumes, and implicit surfaces.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |