Currently, custom model vertices increase the geometry complexity, but the limit might be tuned differently based on performance feedback. The amount of textures being used is currently not shown anywhere or capped. Visibility into this will come soon.

Open edges are supported. Horizon doesn’t use double-sided shaders, so if you are creating objects with two sides, such as leaves, you will need to create polygons that face both directions.

Horizons lighting solution (RTK) uses vertex colors to add lighting information to the scene. When modeling with this in mind, it becomes easy to visualize and control where light and shadow appear on the finished model once baked. The fidelity of the applied lighting is directly related to the density and placement of vertices.

It is important to plan your topology to support different lighting scenarios. Identify which parts are in shadow, and how that shadow transitions into light.

Problem The top example shows how vertices can define light and shadow:

Solution: The meshes in the bottom example solves this problem by adding in a vertex in the center of the cube sides where it intersects the bar to define the shadow. It places support loops on the center bar to define which area is in the light.

Build objects on real-world scales. Make sure that when you export your FBX, the units are set appropriately.

Houdini - Check “Convert Units” on the FBX export ROP.

Maya - The is a known scale issue where models will come in at the correct size but will have their transforms set to 0.01 scale.

When exporting a set of objects, we recommend setting their pivot correctly, centered at the bottom of each piece, or aligned in the same way that you would for a well-prepared game asset.

Tip: currently, pivots will all become centered in Horizon, but this is something we plan to change in the future, so setting up your pivots correctly now could make these assets more useful in the future.

See the Fallout 4 Modular Level Design talk for pivots, standardizing, and more tips around this.

Consider breaking your asset into pieces if those pieces would be useful for remixing.  However, if you aren’t planning on remixing an asset, it’s better optimized as a single piece.

Maya - Prior to exporting from Maya, you should group your kit, then arrange it in a way that is convenient to see and access all of the items in your kit. We recommend that the history is deleted and the transform is frozen.

Because we use the lowest mip size for coloring the bounce lighting information, there is a possibility that closely-packed UVs with strong color differences could cause incorrect color bouncing. If you have UV islands with strong color differences, you should use extra UV padding between those islands.

Minimum padding you should use for large color differences:

Because the Quest 2 screens are high resolution, you can get extremely close to object surfaces. This makes it challenging for textures with fine details to remain good-looking when you are very close to them or they are very large. We recommend creating textures with less high-frequency detail, a style which holds up well in VR.

Model baking is a common technique. Keep in mind that we currently do not support normal maps, so use geometry to convey information you typically migh put into a normal map.  Using geometry instead of normals works very well in VR and gives you nicer kitbash piece intersections when laying out worlds.

One of the best ways to optimize your textures is to use what are called trim-sheets, also known as artist-authored texture atlases. These are tiled strips of re-usable texture information that is assigned with UV coordinates onto different parts of the model.

Examples showing basecolor + roughness compared to basecolor + roughness + metalness.