Reset transforms
Before exporting the file, ensure that the object’s position, rotation, and scale are reset. Upon importing the file into any 3D software, confirm that its location and rotation values are set to zero, while the scale is adjusted to 100%.
In 3ds Max:
In Blender:
Centered origin
The geometry pivot must be aligned to the mesh, with the Z value positioned at the lowest point of the object. Subsequently, the object should be centered in the scene, ensuring that the model’s bottom rests on the ground plane without any floating or placement below it.
No extra objects
The model file should exclusively comprise the mesh object(s) and should not include any cameras, lights, dummies, or additional objects. However, if the model is animated, it may include bones or an armature.
Realistic object scale
If the model is based on a real object for reference, ensure that its size closely aligns with the scale of the actual object. In the absence of a real reference, set the scale to create a realistic appearance; for instance, a typical height for the seat of a simple chair is generally around 45cm.
Unique names
Ensure that every object or material is assigned a unique name to avoid issues arising from identical names for different objects. If your model includes objects with similar names, consider adding numbering to distinguish them.
No special characters
Refrain from incorporating non-standard characters in naming; stick to using letters, numbers, and symbols such as underscore (_) and hyphen (-). Some software may not recognize non-English letters and other special characters, leading to incorrect appearances.
Consistent naming
Maintain consistency in your chosen naming structure. For instance, if you opt for numbering to differentiate between various objects, ensure the same numbering structure is applied consistently across all of them.
No empty spaces
Avoid incorporating spaces in object or material names; utilize symbols such as underscores (_) or dashes (-) instead of spaces.
No N-gons
Construct the mesh using a combination of quads and triangles, avoiding the use of n-gons. It is advisable to minimize the number of triangles and maintain quads without triangulation whenever feasible. Keep in mind that when importing into most game engines or converting into specific formats, the geometry may be automatically triangulated. In some instances, pre-triangulating certain faces is recommended to prevent incorrect triangulation that could result in shape or shading issues, particularly with non-convex faces.
No non-manifold geometry
Non-manifold geometry typically refers to geometry that lacks realistic existence and cannot be unfolded into a 2D shape. This issue commonly arises when a single edge is shared by more than two faces. It is crucial to avoid non-manifold geometry, as it can lead to various technical issues, rendering the model unusable in certain software applications.
No backfaces
It’s recommended to avoid visible backfaces. If both sides of a face are intended to be visible, it’s advisable to incorporate inside geometry or thickness to that region. While backface visibility can be enabled in game engines and software, it should not be solely relied upon, as backfaces may introduce technical problems or limitations.
Smoothed geometry
Apply some form of smoothing to the geometry; it should not appear entirely faceted. Assign at least one smoothing group to the mesh, using as few smoothing groups as necessary.
UV Unwrapping
Ensure that the model has unwrapped UVs to facilitate the application of textures. Even if the model is designed for simple colors, it is recommended to have functional UVs for versatility. Some engines and software may not render or display a model correctly without any UV mapping, potentially causing technical problems and limitations.
No overlapping per UV island
Arrange all UV islands properly, avoiding any internal overlap within each island. Overlapping sections may occur if UVs are not correctly welded, resulting in seams that do not align with the actual geometry. While it’s acceptable for different UV islands to be stacked or overlapped, ensure there are no overlapping components within an individual island.
No texture stretching
Unwrap UVs to minimize visible stretching when applying textures. Generally, this can be accomplished by keeping all UV shells as straight as possible.
No obvious/unnecessary UV seams
Create UVs with minimal seams, and if seams are unavoidable, position them in inconspicuous areas such as along edges or in less visible locations.
Metalness workflow
Configure materials using a standard PBR (Physically Based Rendering) metalness workflow for optimal compatibility across various renderers and engines.
Required textures
For the model to be compatible with PBR materials, a minimum of four main textures is essential: BaseColor, Normal, Roughness, and Metalness. Other textures such as AO, Emissive, and Opacity are optional based on specific requirements. However, in most cases, it is recommended to include an AO map by baking and incorporating it.
Texture resolution
Ensure that all textures have a square 1:1 aspect ratio, with resolutions being powers of 2, such as 256×256, 512×512, 1024×1024, and so forth.
No embedded textures
The exported model file should not include embedded textures, as this unnecessarily increases the file size. Textures are intended to be included separately alongside the model.
Texture color space
Utilize the sRGB color space for color maps such as BaseColor and Emissive, while the normal map should be in the RGB color space. For all other maps, employ the linear color space. Ensure that the color space is accurately configured for each texture map to guarantee proper functionality.
Image color mode
Configure textures that depend on color, such as BaseColor or Normal maps, to RGB mode. For textures that solely rely on black or white values, like Roughness or AO, set them to Grayscale mode.
Naming convention
For simplicity and consistency, it is advisable to adopt a naming convention with the structure {Material}_{Texture type}.{file_format}, where {Material} corresponds to the material name applied to the model. For instance, use “Sofa_BaseColor.png” as an example.
Transparent materials
If any parts of the model incorporate transparency, it is essential to employ a distinct material for those sections separate from the opaque parts. Using the same material for both opaque and transparent elements often leads to complications.
No objects without materials
Each geometry object should have at least one material applied; the absence of any material on objects can result in issues.
FBX Format
- Only Binary FBX files are allowed.
- Make sure that during the export FBX file format type is set to Binary.
- FBX version 7100 or later (FBX 2011 or later in 3ds Max FBX exporter)