3D Scene Setup
You should always conform your content to the standards and conventions presented by UE4. Most of these are technical in nature, many are stylistic, but all have good reasoning behind them.
You must start by organizing your source art files (your Max, Maya, and Photoshop files). Organization is the name of the game and taking the time now to get it right is important.
Changing names, scale, vertex count, pivot points, and so on are all very easy to do in Digital Content Creation (DCC) apps—just click, rename, move, and scale. These apps were made to modify Meshes and bitmaps and are good at it, and you’re probably good at using them to do that. Doing these things is much more involved (if they are even possible) after you have your content into UE4.
Unreal Engine 4 uses centimeters as the default scene unit. Ideally, always set your applications to work in a 1 unit == 1 cm unit scale. However, for a lot of visualization, this is not as easy as it seems. We are often beholden to source data limitations or other workflow imperatives that prevent us from easily doing that conversion.
A few ways exist to alleviate this issue. The FBX exporter enables you to apply a scale to Meshes while exporting, and UE4 offers an import scale (and rotation) setting for Meshes. These options might or might not work depending on your content and isn’t recommended if you can help it. Instead, try to find a way to rescale your content prior to export.
Max also offers the option to set Display Units. This option does nothing to the data or scene. It is simply a conversion from the scene unit scale to the visual elements in the UI. This lets you keep your content in centimeters and continue to work with familiar units.
Getting accurate statistics is essential for optimizing your content. The most important ones are Triangle and Vertex counts. Note that I said triangle not poly or faces or any other terminology. UE4 breaks down all geometry to triangles defined by vertices for rendering, so anything else is unimportant for our needs.
Backface Cull and Normals
Backface Cull is a rendering optimization where triangles aren’t rendered if they are facing away from the camera. This can also be known as two-sided or double-sided rendering.
Many 3D applications have two-sided rendering enabled by default, showing both sides of objects. This can give you an incorrect view of the geometry because UE4 culls back-facing triangles by default. You can set individual materials and material instances in UE4 to be two-sided, but it’s not an efficient fix and isn’t intended to fix bad content, but is a feature to render specific surfaces such as foliage.
You should turn off two-sided rendering in your 3D applications to ensure you are looking at the same model that you will see in UE4. Fix any face and vertex normal issues in your 3D application before exporting to UE4.