CAD File Formats



This page describes how Datasmith imports scenes from most supported CAD file formats into Unreal Editor. It follows the basic process outlined by the Datasmith Overview and Datasmith Import Process pages, but adds some special translation behavior that is specific to CAD files. If you're planning to use Datasmith to import scenes from CAD files into Unreal Editor, reading this page can help you understand how your scene is translated, and how you can work with the results in Unreal Editor.To get more news about download cad, you can visit shine news official website.

In CAD formats, you often use curves and mathematical functions to define surfaces and solids. The precision and smoothness of these surfaces is ideal for the manufacturing process. However, modern GPU chips are highly optimized for rendering surfaces that are made up of triangular meshes. Real-time renderers and game engines like Unreal, which need to push the limits of these GPUs in order to produce dozens of stunning photoreal quality images every second, typically only work with geometry that is made up of triangular meshes.

Datasmith bridges this gap by automatically computing triangular meshes that closely approximate any curved surfaces in your CAD file that don't already have mesh representations. This process is called tessellation, and it is an essential step in preparing your CAD data for use in real time.

For example, the image on the left shows a surface rendered in a native CAD viewer. The image on the right shows a wireframe of a triangular mesh that was generated for that surface.
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.
Lowering the value of this parameter makes the tessellated surface stay closer to the original surface, producing more small triangles.

The effect of this setting is most visible in areas with greater curvature: as the tolerance value increases, the generated triangles become larger and the surface smoothness is reduced.