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rhino:meshfaqdetails [2016/03/15] |
rhino:meshfaqdetails [2020/08/14] (current) |
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+ | ====== Rhino Mesh Settings - Detailed Info ====== | ||
+ | >// | ||
+ | |||
+ | <color slategray> | ||
+ | |||
+ | // | ||
+ | |||
+ | |||
+ | =====Why am I here?===== | ||
+ | |||
+ | **//Pretty much everyone// | ||
+ | |||
+ | * getting a //faceted rendition// of what should be a nice, smooth curved surface | ||
+ | * a display that //slows to a crawl// with a large model | ||
+ | * mysterious //ghost surfaces// showing up in unexpected places | ||
+ | * invisible surfaces or whole objects | ||
+ | |||
+ | All these can usually be traced back to some problem with the meshing of the model or your mesh settings in general...\\ | ||
+ | |||
+ | <color darkslateblue> | ||
+ | |||
+ | Well, you may not know it, but you created some meshes without realizing it ... //read on//. | ||
+ | |||
+ | =====Why do we need meshes? | ||
+ | Although Rhino is a [[rhino: | ||
+ | |||
+ | Why? For quick shading and rendering. | ||
+ | |||
+ | The same meshing engine in Rhino is used in both the creation of analysis meshes for the functions like Draft Analysis and Curvature Analysis, EMap and by the **Mesh** command (//Tools > Polygon Mesh > From NURBS Object//), which creates a real mesh object directly from a NURBS object. | ||
+ | |||
+ | Exporting from Rhino with certain polygon-based formats (such as .stl) will also create mesh objects (in the exported file). | ||
+ | |||
+ | The functions that create real, editable meshes like **Mesh** and **Export** (.stl) are important in many applications, | ||
+ | |||
+ | All the types of mesh objects can exist simultaneously in one file. They do not affect one another and each can have its own settings. Although all the meshes are created with the same engine, there are a couple of important differences between them. | ||
+ | |||
+ | =====The different mesh types===== | ||
+ | |||
+ | * **Render meshes** are created on [[rhino: | ||
+ | |||
+ | |||
+ | * **Analysis meshes** are like the render meshes in that they are not normally editable or separable from their NURBS object. | ||
+ | |||
+ | |||
+ | * **Meshes created by the Mesh command** are visible and editable, and are separate from the NURBS objects they were created from. They are objects in their own right. View and edit them with the various Rhino commands that apply to meshes (see //Bonus > Mesh//). They can be exported to in polygon mesh formats like STL, DXF, 3DS, and OBJ. | ||
+ | |||
+ | |||
+ | * **Meshes created during Save and Export** (such as .stl) have the same mesh settings dialogs (" | ||
+ | |||
+ | > <color slategray>// | ||
+ | |||
+ | |||
+ | =====The mesh settings dialogs===== | ||
+ | |||
+ | <color darkslateblue> | ||
+ | |||
+ | <color darkslategray> | ||
+ | |||
+ | <color darkslateblue> | ||
+ | |||
+ | <color darkslategray> | ||
+ | |||
+ | So meshing is a balancing act. The idea is to use the //least// number of mesh faces you need to have adequate resolution for your job -- and no more. To do that in Rhino requires some understanding of how the meshing system works. | ||
+ | |||
+ | ====The Controls==== | ||
+ | The controls for different mesh types are virtually identical. | ||
+ | |||
+ | When creating a mesh from a NURBS object, or exporting to a mesh format like STL, DXF, 3DS, and OBJ you can use the simple controls, which are just a coarse <==> fine slider: fewer <==> more polygons. | ||
+ | |||
+ | Or, there are the detailed controls which expose more of the settings. | ||
+ | |||
+ | ====The default settings==== | ||
+ | * **Jagged & Faster** is the default for render meshes --- fine for quick visualization, | ||
+ | |||
+ | * **Smooth & Slower** // | ||
+ | |||
+ | * **Custom** offers the most flexibility in tailoring the mesh settings, at the expense of being a bit complex to understand and set up. | ||
+ | |||
+ | * The default simple slider settings for analysis meshes as well as Mesh and Export is an average //" | ||
+ | |||
+ | * The default setting for the special STL Export dialog is generally the last used //max dist edge to srf// setting in the custom dialog or the value of Absolute Tolerance in //File > Properties > Units// if none was set. | ||
+ | |||
+ | ====The Custom settings==== | ||
+ | |||
+ | **If you really want to control your meshing process, here is where you need to start!** | ||
+ | |||
+ | There are //seven// numerical settings and //three// check boxes. | ||
+ | |||
+ | |||
+ | **Some quick guidelines** | ||
+ | |||
+ | Below is a basic start point for custom settings. Experiment with them on your models.\\ | ||
+ | |||
+ | //If a setting is 0 or 0.0, it is turned off (not taken into a account).// | ||
+ | |||
+ | |**Density** //(new in Rhino 4)//| <color slategray> | ||
+ | |**Maximum angle**| | ||
+ | |**Maximum aspect ratio**| | ||
+ | |**Maximum edge length**| | ||
+ | |**Maximum distance edge to surface** | ||
+ | |**Minimum initial grid quads**| | ||
+ | |||
+ | > <color slategray> | ||
+ | |||
+ | * Refine mesh **checked** | ||
+ | * Jagged seams **// | ||
+ | * Simple planes **// | ||
+ | |||
+ | * The **Maximum distance edge to surface** method forces Rhino to create a mesh that is no further away from the surface than the specified value, which is in current file units. | ||
+ | * The **Minimum initial grid quads** setting makes sure the flatter areas have enough polygons to look smooth. | ||
+ | |||
+ | > <color darkslategray>// | ||
+ | |||
+ | > <color darkslategray>// | ||
+ | |||
+ | > <color darkslategray>// | ||
+ | |||
+ | > <color darkslategray>// | ||
+ | |||
+ | **The main setting is the one for //max distance edge to surface// | ||
+ | |||
+ | <color darkslateblue>// | ||
+ | |||
+ | First, it depends on what you're going to be using your mesh setting for. For general display purposes your value can be a bit bigger (looser), as you're only visualizing the model on your screen, and less polygons mean faster meshing times and quicker display reaction when tumbling, zooming, etc. | ||
+ | |||
+ | * If you are doing computer-sized objects, 0.01mm works out pretty well. For watches and jewelry, you will probably want it smaller, maybe .002mm. For larger objects like buildings, much larger, maybe 1mm or even larger. | ||
+ | |||
+ | * If you plan to export your object for later processes, or do very detailed renderings, you may need to tighten up the settings a bit, depending on where it's going and how precise the process is. For a stereolithography part for example, .01mm should still be fine, but for a good machined part, .001mm-.002mm is probably more appropriate. | ||
+ | |||
+ | It may seem very complicated at first, but after a bit of practice, you will find a few standard settings that work for you in most situations. | ||
+ | |||
+ | <color darkslategray> | ||
+ | \\ | ||
+ | //The Density number feeds Rhino something to use in its own internal calculation, | ||
+ | |||
+ | =====Known meshing problems and weaknesses===== | ||
+ | |||
+ | Sometimes, you may find that even with the settings guidelines above, you are still not getting good results. | ||
+ | |||
+ | ====Things to watch out for==== | ||
+ | //These conditions don't always cause problems meshing, but they have been known to do so in the past. So if you are having difficulties, | ||
+ | |||
+ | * <color darkslateblue> | ||
+ | |||
+ | * <color darkslateblue> | ||
+ | |||
+ | * <color darkslateblue> | ||
+ | |||
+ | * <color darkslateblue> | ||
+ | |||
+ | * <color darkslateblue> | ||
+ | |||
+ | =====Diagnostics (From the Rhino Help file)===== | ||
+ | |||
+ | **[[rhino: | ||
+ | |||
+ | ---- |