TABLE OF CONTENTS


  1. Introduction
  2. 3D Data Types & Formats
  3. Supported 3D Features
  4. Material Support
  5. DCC Tool Export Guidelines
    1. Autodesk 3ds Max
    2. Autodesk Maya
    3. Blender
    4. Modo
    5. CLO 3D
  6. Game Engine Import Guidelines
    1. Unreal Engine
    2. Unity 3D
  7. 3D Scan Guidelines


1. Introduction


As a 3D Data Optimization Solution, RapidCompact relies on clean and functional input data. This applies mostly to Materials & Shading, but also to a certain extend to Texture Mapping and Geometry data.


RapidCompact is not a Remesher or traditional LOD Generation tool, but instead a 3D Data Simplifier capable of preserving and simplifying PBR material information in addition to simplifying meshes, node structures and input textures as well as baking material information or vertex colors. Therefore properly set-up input data is key for a smooth optimization process.





Left: Optimized with RapidCompact using Atlas Baking (rebaking) method; Right: Unoptimized source data



Here are some good rules of thumb of verifying the integrity of your input data:


  • Can the asset be loaded into DCC tools such as Blender?
  • Does the rendering result look correct?
  • Does it consist of polygonal data?
  • Are textures and materials correctly assigned?
  • Does the file contains one asset or multiple assets*? The latter should be avoided
  • In case of 3D scanning. Is the pointcloud data already converted into a mesh?
  • Are the mesh normals pointing in the right direction? (RapidCompact can handle outliers)
  • Does the input dataset make heavy use of procedural generated materials & nodes? (see material section here)


*Asset definition: Coherent dataset which is set-up for deployment or further optimization, this can be one mesh, multiple meshes or a whole scene.


We also recommend some general guidelines for creating or converting to real-time assets:






2. 3D Data Types & Formats


Supported 3D formats:


FormatInput (Upload)Output (Download)
GLTF/GLB .gltf .glbyesyes
USDZ .usdznoyes
FBX .fbx .FBXyesno
OBJ .objyesyes
PLY .plyyesyes
STL .stlyesyes
JT .jt*yesno
STEP .stp .step*yesno
IGES .iges*yesno

* Requires a RapidCompact Enterprise Plan


Supported 2D formats:


FormatInput (with 3D Format)Output (with 3D Format)
JPEG .jpgyesyes
PNG .pngyesyes
TGA .tgayesno
KTX2 .ktxnoyes


Other supported formats:


FormatInput (Upload)Output (Download)
ZIP .zipyesyes





3. Supported 3D Features


FeatureInput (Upload)Output (Download)
Rigid Animationyesyes
Skinned Animationnono
Morph Targets (Blend Shapes)nono
Scene Lightsnono
Mesh Compression (draco)yesyes
Texture Compression (basis)noyes






4. Material Support


In general RapidCompact supports the following material properties:


Material PropertyImport (Upload)Export (Download)
Material Colorsyesyes
Vertex Colorsyesno
Materials using Texture Maps (PBR)yesyes
Materials using repeating UVs & tiled Texturesyesyes
Materials using procedual nodesnono
Materials using render-specific shading nodes (eg. vray)nono




RapidCompact supports PBR Material systems such as the one supported by glTF 2.0, physical material for 3D Studio Max or Stingray PBS for Maya. 


This means that all glTF/glb datasets exported by any DCC tool will work flawlessly with RapidCompact (if no custom extensions are used).



MaterialSupport
PBR (glTF, USDZ)yes
Physical Material (3DsMax)yes
Stingray PBSyes
VRayno
Coronano
Arnoldno
3DsMax Standard Materiallimited
Principled BSDF (Blender)limited (.glTF/.glb)






5. DCC Tool Export Guidelines


The following section introduces best practises for exporting data from various DCC tools. As the tools can be quite different in usability, use-case and functionality we will go into detail with each tool and highlight the steps for creating valid input data for further processing and optimization towards real-time content.




Autodesk 3ds Max


For the best possible outcome we recommend using the editable poly surface modifier for all 3D data. Subdivide and other modifiers operating and/or altering the meshes raw geometry data as well as render-specific modifiers (eg. VrayDisplacementMod etc.) should be merged with the editable poly if they are supported or get ignored if they are not supported.


Concerning materials there are similar roadblocks when going from offline-render-specific material systems (see section above) to real-time representations. Thus we would recommend using the 3D Studio Max Scene Converter feature:




Left: Rendering->Scene Converter; Right: Select the material/render model the scene was initially set-up with, to convert it to physical material



For exporting the data we recommend using fbx 2020 with the embed media option checked. The resulting fbx are then supported by RapidCompact.


Alternatively tools such as the Babylon glTF Exporter can be used (It's the same approach but uses glTF as export format). 




Autodesk Maya


The recommended export steps for Autodesk Maya are the following:


  • Stingray PBS Materials 
  • Export fbx 2020 with embed media option (similar to 3ds Max export settings above)


Stingray PBS Material can be found in the Hypershade Editor




Blender


As stated in “4. Material Support” Principled BSDF shader’s supported channels are: 

Base Color / Metallic / Roughness / Normal / Ambient Occlusion / Emission


If exported as glb/glTF the properties of those channels will be readable in Rapid Compact. 

With other supported file formats please make sure there are textures connected to and exported with the PBR supported channels.

 

Supported channels highlighted in green




Modo


Materials that support the PBR model in Modo are the Principled Shader, gltF Material, Unity Material & Unreal Materials.

 

The Modo PBR Loader can help with importing PBR textures into Modo within your texturing workflow.


Left: PBR loader can be found in Texture/PBR;  Right: Materials with supported textures



CLO 3D


If the starting point of the 3D workflow is in 3D apparel software such as CLO 3D we recommend the following export settings:


  • .glTF/.glb format
  • Object options "Thin" and "Single Object" have to be ticked
  • File settings: "Save Colorway" + "Maintain Individual Texture Image Coordinates"


Left: Navigation inside CLO 3D to glTF/GLB export; Right: Recommended GLB export settings



For further export options see the CLO 3D Export Options Documentation.







6. Game Engine Import Guidelines


Often, assets optimized with RapidCompact are not directly deployed on the web or in app-less (AR) functionalities, but are also being used in Game Engines and other platforms building real-time interactive experiences.


In this section we highlight general best practises of getting the optimized data into Editors such as Unreal and Unity 3D.




Unreal Engine 4


For Unreal Engine we reccomend the following import options:


  • Import .glb files (advantage: PBR materials are automatically set-up, assets are matching RapidCompact Output)
  • Scale factor should be 100 by default (coming from meters in glTF/glb going to centimeters in unreal)
  • The flip from Y-Up to Z-Up is handeled automatically when importing gltf/glb


Unreal Engine glTF Import Options, generate Lightmap UVs is recommended



By default unreal engine imports gltf normal maps without flagging them as those leading to visual errors. 


Solution:

  1. Set the map in the texture editor's compression settings to Normalmap and flip the green channel.
  2. Go into the respective materials fixing the map channel of the normal map node to "Normal" and hook up the normal map node directly into the normal slot of the material, ignore the shader network which was set-up in the first place.



Correct Material set-up for glTF normal maps as described above (subject to change depending on unreal improvements).



Left: FlightHelmet asset rom glTF with wrong normals; Right: After applying the steps above



As you will realise with multi-part assets (such as unoptimized data, complex multi mesh node objects or assets with opacque vs transparent materials and nodes) these have to be combined into a single in-game "actor". In Unreal this works a bit different compared to the "prefab" system in Unity (see section below). 


To merge parts of multi-part assets into a single actor use the following guidelines:


  1. Put the parts into the scene, zero their translations so they are in the origin of the scene. Select all parts which should be merged.
  2. Go to Window -> Developer Tools -> Merge Actors
  3. Accept (usually default settings are reasonable) and save into a new directory
  4. Delete the original assets in the scene
  5. New merged actor can be placed (settings, materials & LODs should be merged as well)



Left: Merge Actors Setting; Right: Select actors to merge




Unity 3D


Similar to the workflow with unreal we would recommend using the .glTF/.glb format for importing your assets from RapidCompact. OBJ is possible too, but forces the recreation of materials, texture import and assignments inside Unity.


Other than Unreal, Unity 3D has no official glTF support and thus relies on plugins/packages by the developer community.

There are alot of glTF importers for Unity out there. 


We would recommend glTFast as we have a very positive experience with the developers and the tool itself. The following features come with this import tool:


  • Runtime import
  • Fast and small footprint JSON parsing
  • Multi-threading via C# job system
  • Editor import
  • Core glTF features
  • full list here


Simply install the package of your choice and start importing glTF/glb files.




7. 3D Scan Guidelines


RapidCompact is especially efficient in simplifying 3D scanned data due to the strong research background of DGG in this area. Whichever scan method or software is used, the following points should communicate some important guidelines:



  • Please calculate mesh/ tesselate before exporting. No point clouds, only mesh data
  • If exported in PLY format make sure the vertex colors are correctly exported
  • If exported in OBJ format make sure the .mtl file is correctly exported and later part of the (zipped) upload data
  • Please take the upload limit of RapidCompact (free plan 500MB) into account when exporting data
  • In general there is no upper limit for triangle count (Up to 250 mio triangles per mesh tested)