Objective:
Learn how to create a Surface Mesh.
Applies to:
- Modeling
- Simulation
- Manufacturing
- Optimization
Procedure:
Based on your workflow, you usually start with either an Implicit Body or a CAD Body. In this example, we will start from an Implicit Body. We recommend using the FE Volume Mesh from CAD if you plan to generate an FE Volume Mesh for Simulation or Optimization.
The Mesh from Implicit Body generates robust and error-proof meshes for complex geometries.
If you wish to use the older version of the Mesh from Implicit Body block, you should use the Mesh from Implicit Body by DC block, which uses the Dual Contouring and has lesser computational overhead. However, the result may contain self-intersections and non-manifold edges.
The inputs for the Mesh from Implicit Body block are listed below:
- Tolerance: Translates to the voxel size. The voxel size is given by half the input tolerance. Using a tolerance equal to 0.5 times the thickness of the smallest feature is recommended. This value will typically exceed the accuracy of most additive manufacturing processes.
Note: As a rule of thumb, the number of triangles in the unsimplified output mesh quadruples whenever the tolerance input is halved. Keep that in mind to avoid generating unreasonably large meshes. If you only use this input, the output mesh is guaranteed to be watertight and manifold.
- Min. feature size: If you provide a feature size, the block performs a filtering step to remove any features or holes smaller than the provided input. You can use this input if the output mesh captures details that are not manufacturable.
- Sharpening option: Enable this to reconstruct sharp features in the implicit body. Typically, enabling the sharpening option improves the mesh's approximation quality significantly. Thus, in practice, decreasing the tolerance input and enabling sharpening to obtain a given target tolerance between the mesh and the implicit is often possible.
Note: Enabling this option will substantially increase the block's runtime; typically, it will take more than twice as long.
- Simplification option: This option produces a mesh with the fewest triangles while still conforming to the input tolerance. Enabling this option will substantially increase the block's runtime.
Note: Similar to the old version, the simplification process can introduce new mesh defects (self-intersections and overfolds). The Simplification option forcibly decimates and combines ~ 90% of the elements, which can result in a loss of geometry fidelity. The Simplifying Mesh By Threshold block allows you to tune the decimation percentage.
Left: Mesh from Implicit Body with sharpening and simplification option enabled. Right: Mesh from Implicit Body by DC with adaptivity set to 0.5.
The block has an overload, which provides even more inputs. In particular, it gives a “Sharpening Extent” input. This can be used to localize the sharpening to some mesh areas. It also provides a “Sharpening iterations” parameter, which can potentially be used to run the sharpening algorithm multiple times to increase the quality of the sharp feature reconstruction.
We often don’t need every edge in our model to remain sharp when using the Sharpen option. Generally, we are concerned with specific regions where we apply boundary conditions for analysis and have GD&T requirements for machining, assembly, and other applications. Therefore, using the Overload to expose the Sharpen Extents option and the Sharpen Iterations is recommended. This option helps decrease the time spent meshing and reduces the overall element count.
When generating the implicit body that encloses the region where we want to keep edges sharp, we suggest it be as localized as possible (i.e., enclose just the area you intend to stay sharp rather than having an oversized implicit).
When using either the Sharpen or Sharpen Extents options, the mesh near the edges defined to remain sharp can sometimes have skinny triangles. Image #1 below shows a 0.5mm thick walled T
PMS with a thin green body encloses the edges, which remain sharp. Image #2 below (left) shows the overall mesh of the part, and (right) shows a zoomed-in section at one of the edges. Encircled in red are fragile triangular elements. These small elements can cause a few issues downstream.
Image #1: Body to mesh (grey) and implicit used (green) to enclose the edges where we want to preserve sharpness.
Image #2: Mesh from Implicit Body (with extents). Left: Full mesh. Right: Zoomed in on edge, encircling thin elements.
| Block | Mesh |
| Mesh from Implicit Body | |
| Mesh from Implicit Body with Sharpen enabled | |
| Mesh from Implicit Body with Sharpen Extents overload |
And that’s it! You’ve successfully created a surface mesh on your part.
Do you still need help? Contact the support team, and we’ll be happy to help!