Where can I find this command?
The Mesh properties manage the mesh settings for the current model.
Whenever you shade or render a NURBS surface, the surface first converts into a polygon mesh. These detailed render mesh options control the way in which the NURBS surfaces convert to polygon meshes.
You may want to adjust these values if you are not satisfied with the default shade and render quality.
Notes
| ● | The meshes created with the Mesh command are visible and editable and separate from the NURBS objects they were created from. |
| ● | The meshes created by any shaded viewport display mode on NURBS surfaces and polysurfaces are invisible, not editable, and cannot be separated from the NURBS object, except to destroy them with the RefreshShade command or to use the ExtractRenderMesh command. |
Render mesh quality
Jagged & faster
Uses a lower density mesh to shade objects more quickly with some loss of quality.
Smooth & slower
Uses a higher density mesh to shade objects more accurately with some loss of speed.
Custom
Displays simple polygon mesh controls.
The mesh is drawn as a preview in the viewports, and the dialog box stays on screen for more adjustments.
Custom options
Density
Uses a formula to control how close the polygon edges are to the original surface. Values between 0 and 1. Larger values result in a mesh with a higher polygon count.
Detailed mesh controls
Note: How meshes are created
A mesh is created in three steps based on the detailed criteria:
| ● | The number of initial quads (estimated to roughly meet the criteria) |
| ● | Refinement (subdivision to meet the criteria) |
| ● | Adjustment for trim boundaries |
Surfaces are meshed in a two-step process. First a regular quadrangle mesh is created and then that mesh is refined by splitting some quadrangles into four smaller quadrangles. The Maximum aspect ratio, Maximum edge length, and Minimum initial grid quads settings control the generation of the initial mesh. The Maximum angle, Maximum edge length, Minimum edge length, and Maximum distance, edge to surface settings determine which initial quadrangles get split up into smaller quadrangles.
Maximum angle
Sets the maximum allowable angle between input surface normals at neighboring mesh vertices. If the angle between surface normals is greater than this setting, the mesh is further refined (more vertices are inserted) and the mesh is made denser. Two vertices are neighbors if they are at the opposite ends of a single facet edge.
The Maximum angle setting will influence the meshing of objects of the same shape in the same way regardless of the size of the objects. It will tend to make meshes denser in areas of high curvature and less dense in flatter areas.
Maximum aspect ratio
Surfaces are initially tessellated with a regular quadrangle mesh and then that mesh is refined. The initial quad mesh is constructed so that on average, the maximum aspect ratio of the quads is less than or equal to Maximum aspect ratio.
Smaller values result in slower meshing and a higher polygon count with more equilateral and nicely shaped polygons. This is approximately the maximum aspect ratio of the quads in the Minimum initial grid quads. Setting Maximum aspect ratio to zero turns off the option. Zero means no limit.
The default value for this option is zero and the suggested range, when not zero, is from 1 to 100.
This setting is scale independent.
Application
When shading long, skinny objects, use 0.0 for the this value. This allows infinite ratios. Control the smoothness of the mesh with other parameters.
Minimum edge length
If any edge is shorter than the Minimum edge length, no further division of the mesh faces occurs. This is also, approximately, the minimum edge length of the quads in the Minimum initial grid quads.
The default value for this option is 0.0001 units and the usable range depends on the size of the model. Bigger values result in faster meshing, less accurate meshes and a lower polygon count. Setting this value to zero turns off the minimum edge length option.
This option is scale dependent.
The value is always in the current unit system.
Maximum edge length
Polygons are further divided until all polygon edges are shorter than this value. This is also, approximately, the maximum edge length of the quads in the Minimum initial grid quads.
Smaller values result in slower meshing and a higher polygon count with more equally sized polygons. Setting this value to zero turns off the option.
The default value is zero and the usable range depends on the size of the model.
This option is scale dependent.
Application
Use for making sure the polygons are approximately the same size.
Maximum distance, edge to surface
Polygons divide until the distance from a polygon edge midpoint to the NURBS surface is smaller than this value. This distance is also the approximate maximum distance from polygon edge midpoints to the NURBS surface in the Minimum initial grid quads.
Smaller values result in slower meshing, more accurate meshes, and a higher polygon count. Setting this value to zero turns off the option.
The default value is zero and the usable range depends on the size of the model.
Application
Use as a general polygon mesh tolerance setting.
Minimum initial grid quads
Initial mesh grid is a quad mesh Rhino creates on each NURBS surface in the first stage of meshing. When the initial mesh grid is made, trim curves are ignored. After the initial grid is made, Rhino meshes all trim edges, connects the initial grid to the trim edges and then refines the mesh if the Refine mesh option is selected.
The number of quadrangles per surface in the initial mesh grid. In practice, Rhino will use at least this many polygons on each surface.
Bigger values result in slower meshing, more accurate meshes and a higher polygon count with more evenly distributed polygons. Setting this value to zero turns off the option.
The default value is 0. The suggested range is from 0 to 10000.
This option is scale independent.
Application
Use to make sure that surfaces with very subtle details are meshed with a high enough polygon count.
Refine mesh
After its initial meshing, Rhino uses a recursive process to refine the mesh until it meets the criteria defined by Maximum angle, Minimum edge length, Maximum edge length, and Maximum distance, edge to surface options.
The mesh is refined until the angle between surface normals along a polygon edge is smaller than this value. The default is 20 degrees and the suggested range is from 5 to 90 degrees. Setting Maximum angle to 0 turns off the option. Scale independent.
No refinement results in faster meshing, less accurate meshes, and lower polygon count. Clearing this check box also means untrimmed individual surfaces and surface areas away from trim edges and joined edges are meshed with evenly sized quadrangles.
Jagged seams
All surfaces mesh independently and Rhino does not stitch the edges of joined surface edges together. Meshes for each surface in a polysurface do not necessary meet to form a watertight mesh.
If Jagged seams is not checked, watertight meshes are created.
This causes faster meshing, a lower polygon count and cracks between joined surfaces in the rendered image.
Application
Rhino does not support watertight quadrangle meshes unless you are meshing a single untrimmed surface. In this case, clear Refine mesh and use Jagged seams to generate quadrangle meshes.
Simple planes
All planar surfaces are meshed by meshing the surface edges and then filling the area bounded by the edges with triangles.
Causes a slower meshing and a minimum polygon count on planar surface, especially for complex trimmed surfaces.
If Simple planes is selected, the settings, except Jagged seams, are ignored for planar surfaces and the planar surface is meshed with as few polygons as possible.
Closes the detailed controls.
See also
Rhinoceros 5 © 2010-2015 Robert McNeel & Associates. 17-Sep-2015
