Twilight Render is described as ', one of the photorealistic 3D rendering systems for SketchUp,'. There are more than 25 alternatives to Twilight Render for a variety of platforms, including Windows, Mac, Linux, Sketchup and Autodesk 3ds Max. The best alternative is Adobe Dimension. It's not free, so if you're looking for a free alternative, you could try LuxCoreRender or POV-Ray. Other great apps like Twilight Render are appleseed (Free, Open Source), RenderMan (Free Personal), Mitsuba (Free) and Kerkythea (Free).
Clara.io is a full-featured cloud-based 3D modeling, animation and rendering software tool that runs in your web browser. With Clara.io you can make complex 3D models, create beautiful photorealistic renderings, and share them without installing any software programs.
Pixie is an open source RenderMan renderer for generating photorealistic images. You can compile Pixie on Windows (using Visual Studio 2005), Linux and on OSX (using XCode or unix style configure script).
Thea Render is a state-of-the-art biased/unbiased renderer with a rich set of innovative features, a powerful material system and its own advanced studio, all-in-one. Plugins are available for 3dsMax, Blender, Cinema4D, Rhino, SketchUp and SoftImage.
YafaRay is a free open-source montecarlo raytracing engine released under the LGPL 2.1 license. Raytracing is a rendering technique for generating realistic images by tracing the path of light through a 3D scene.
NOX Renderer is a rendering software based on unbiased methods. The renderer is available as a standalone Windows executable with a plug-in to link it to 3ds Max. A linking script is also available for Blender users.
MiniLight is a minimal global illumination renderer. It is primarily an exercise in simplicity. But that makes it a good base and benchmark (in some sense) for development and experimentation. And it just might be the neatest renderer around (on average, about 650 lines).