EQUINOX-3D has had the first interactive ray-tracer in a 3D modeling application and it's still the only one with a fully integrated ray-tracer.
See below and check out the Image gallery and the screenshots.

• Multi-threading (it uses all the cores on your CPUs).
• GPU ray-tracer in the works (I have a working prototype, but it uses CUDA, so it only works on NVidia GPUs. The new one will use OpenCL).

All renderers are fully integrated in the user interface, meaning:
- Any window can use any renderer. No need to open a separate window for the ray-tracer (you can, if you need to).
- No load time. When you edit your models, they redraw instantly, even in a ray-traced window!

Note the wireframe and 3D controls overlaid on the ray-traced image:



You can also create your own renderer as a plugin, or even a whole video game and run it inside any EQUINOX-3D window.
You can do full editing with the interactive ray-tracer (not just move the camera interactively, as in other applications).
- select and unselect things
- edit 3D models.
- move objects, the camera, lights, change materials etc.
Thanks to intelligent, selective updates, Spline editing, selecting / unselecting, exposure changes and so on, are just as fast on the ray-traced view as on any other one!



• Interactive option for the main render window:
  

  In addition to the regular 3D windows, there is also a traditional, separate window for rendering movies, or images larger than the screen. You can also make this window interactive.
  
  



• Depth-of-field and motion blur. Yes, this is an EQUINOX-3D rendering. You can see the movie here
  
  


• Global illumination / indirect light.
  
  


• Reflected and transmitted caustics.
  
  


• Powerful and fast cross-renderer shader interface (ray-tracer, Cg etc.).
  Per-pixel normals, geometric tangents, texture-space tangents, pre-sampled/shadow-tested area light samples etc. are easily accesible by shaders.
  Source code examples included:
  - Phong with Fresnel-modulated reflectivity and specular highlight
  - Anisotropic shader
  
  Minimal effort needed to implement a shader for both the ray-tracer, the Cg renderer etc. (e.g. the Cg framework automatically generates Cg shaders from a minimal template).
  Identical look for Cg and ray-tracer outputs (within the limitations of graphics hardware):
  

  Ray-tracer

  Cg

  
  
• Multi-texturing
  For example, you can have separate textures for the ambient, reflective etc. colors, or for any parameter of a custom shader:
  
  



• Bump / normal-mapping
  
  



• Area lights
  Any 3D object can be a light source and area lights cast correct soft shadows:
  



• Programmable texture-mappers
  In addition to the built-in mappers (planar, UV, cylindrical etc.) you can write your own mapper that fits a particular object best.
  
  
• Direct support for mirror-ball photograps and angle maps as textures/environment maps
  


• Textured area lights and high dynamic range texture support
  32-bit floating-point values per R, G, B, A channels
  
  


• Colored reflections and refractions
  


• Volumetric absorption (e.g. 'muddy water' effect)
  


• Anti-aliasing with many options
  


• Customizable progressive refinement:
  ->->
  


• Multiple lens types:
   Perspective, Fish-eye, rear-view fish-eye, Cylindrical, Panorama and Angle-map
   (great for creating reflection-maps and illumination-maps)
   
  

• High Dynamic Range (HDR) image support:
  Allows you to save the rendered image with its full color range, as 32-bit floating-point values per R, G, B, A channels.