Tessellating a surface for real-time rendering involves an implicit tradeoff between the accuracy of the surface and the speed that it can be rendered.
By nature, a triangular mesh can never exactly match the mathematically precise surface it was generated from. Tessellation always implies sampling the original surface at some level of detail to create an approximation that allows the GPU to render the geometry more quickly. Typically, the closer your mesh is to the original surface, the more complex it will be — that is, it will contain more triangles, and those triangles will be smaller. This may look better when it's rendered, but places higher demands on the GPU. If you lower the accuracy of your tessellated mesh, so that it contains fewer, larger triangles, the GPU will be able to render it faster, but that rendering may not give you the visual fidelity you're looking for — it may look blocky or jagged.
Therefore, your goal in the tessellation process is to minimize the number of triangles in your mesh, while maximizing its visual fidelity to the source. This usually means that you aim to have a relatively small number of larger triangles in places where the surface is smoother and flatter, and a relatively large number of smaller triangles in places where the surface is more complex and uneven.
Datasmith offers three parameters that you can adjust when you import a CAD scene, described in the following sections. By tweaking these values, you can control the complexity and fidelity of the Static Mesh geometry that Datasmith creates for your curved surfaces.
You can also set these same options when you reimport individual Static Mesh Assets. This allows you to set overall tessellation values for your scene, then override those settings for individual objects that need higher or lower levels of detail. See also About the Datasmith Reimport Workflow