ObjReader 4.00 - the .ORB challenge

[Patrice Terrier]

ObjReader 4.00 - the .ORB challenge

TL;DR: A compact binary format for Wavefront models that loads faster, takes less disk space, needs no extra DLLs, and stays fully compatible with OBJ/MTL.

What is .ORB?
.ORB = ObjReader Binary. It’s a compound file format for ObjReader that preserves Wavefront OBJ/MTL compatibility while dramatically reducing size and load time.

File layout

• PNG thumbnail — preview of the model (visible in Windows Explorer thumbnail view).
  
• Header — a small block storing internal offsets to each data section.
  
• Compressed geometry — mesh data matching the source Wavefront OBJ.
  
• Compressed MTL trailer — verbatim copy of the original .mtl file, stored at the end.
  

Compression: to avoid extra dependencies, .orb uses Windows’ built-in LZNT1 (NTDLL, LZ77-based). No external DLL required.

Explorer thumbnail

The thumbnail embedded in a [.orb] file is created the first time you open the model in ObjReader.
ObjReader renders the current viewport with its OpenGL pipeline (gl_DrawScene) and stores that live capture as the file’s preview.

What it reflects:

• Geometry, materials, and textures actually loaded
• Camera position and FOV
• Active lighting preset and background
• The model’s current pose/orientation

Why it matters: it lets you recognize models at a glance in Explorer and file pickers. The thumbnail is only a preview—it does not affect the model data.

Integration

• File association: .orb is registered to launch ObjReader directly from Explorer.
  
• ObjReader 4.00 size: the new executable is 14 KB smaller than v3.00+, thanks to aggressive code optimization and compiler settings.
  
• ORDLL64 / ORV64: ORV64 and ORDLL64.dll are updated to understand .orb directly; ORV64 can open .orb even if no .mtl is present on disk.
  

Round-trip compatibility

• Export from .ORB: ObjReader adds a menu option: File ? Export .ORB to .MTL/.OBJ.
  
• Console tool: orbtool.exe provides standalone compile/decompile:
  

Compile  (OBJ ? ORB): orbtool -c <input.obj> -o <output.orb>
Decompile(ORB ? OBJ): orbtool -x <input.orb> -o <outputBase>
     (produces <outputBase>.obj and <outputBase>.mtl)

Why this is good

• Smaller files on disk.
  
• Faster loads in memory.
  
• No extra runtime dependencies (uses Windows’ own LZNT1).
  
• Still Wavefront-compatible (verbatim .mtl preserved; lossless geometry).
  

Overall performance

• Disk space: ~50% of the original OBJ/MTL size (typical).
  
• Loading speed: Up to 10× faster on large models (no text parsing; contiguous, precompiled geometry).
  

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Attachments

• ObjReader Version 4.00, is attached to this post.
  
• Orbtool console utility, is attached to this post.
  

[Patrice Terrier]

About ORV_64 v3.10
(sample app for embedding ObjReader via ORDLL64.dll.)



What it is
ORV_64 is a complete C/C++ (VS2022, x64) example that hosts the ObjReader engine through ORDLL64.dll.
The DLL exposes a focused C API, just enough to create a viewer window, load a model, animate it, and query stats.
So you can render ObjReader content inside your own application UI.

What ORDLL64.dll is

• The embeddable runtime of ObjReader (Win64).
• Owns the renderer, model loading (.orb, .obj/.mtl), animation timer, and optional audio sync.
  
• You supply the top-level window and message loop; the DLL creates and manages its child viewport.

Why v3.10 matters,  native .ORB compatibility

• Cuts startup time (no text parsing/reindexing).
• Reduces disk size for large meshes.
• Simplifies packaging: ship model.orb + textures in the same folder.
  

Your code can prefer .orb and automatically fall back to .obj when needed.

Typical integration flow

• Create your main window (CreateWindowExW).
  
• Call OR_CreateWindow(...) to create the viewer child HWND.
  
• (Optional) OR_SetSwapInterval(TRUE) for V-sync, OR_TimerEnable(TRUE) to animate.
  
• Load a file via:

Code: [Select]

OR_ProcessCommandLine(L"path\\to\\model.orb");

• On WM_SIZE, resize the child window.
  
• Populate your UI with getters (OR_Vertices(), OR_Triangles(), …).
  
• Offer controls: OR_ViewReset(), OR_Get/SetAudioVolume(), OR_Screen_Shot().
  
• On exit, call OR_CloseAll().
  

API at a glance (what you’ll actually use)

• Create/host: OR_CreateWindow, OR_CloseAll
  
• Open model: OR_ProcessCommandLine (accepts .orb and .obj)
  
• Animation & timing: OR_TimerEnable, OR_GetAniTick
  
• Display options: OR_SetSwapInterval, OR_ViewReset, OR_Screen_Shot
  
• Info for UI:
  
  • OR_Version, OR_ObjFileName
    
  • OR_Vertices, OR_Triangles, OR_Indices
    
  • OR_Meshes, OR_Materials, OR_ObjSize, OR_LoadTime
    
  • OR_DetectGPU, OR_GPUinfo, OR_GPU, OR_CPU
    
• Audio: OR_GetAudioVolume, OR_SetAudioVolume
  

Attachment

• ORV_64 Version 3.10, is attached to this post.