Indigo Renderer is described as 'Unbiased, physically based and photorealistic renderer which simulates the physics of light to achieve near-perfect image realism. With an advanced physical camera model, a super-realistic materials system and the ability to simulate complex lighting' and is an app. There are more than 25 alternatives to Indigo Renderer for a variety of platforms, including Windows, Mac, Linux, Autodesk 3ds Max and Sketchup apps. The best Indigo Renderer alternative is LuxCoreRender, which is both free and Open Source. Other great apps like Indigo Renderer are MoonRay, Adobe Dimension, POV-Ray and Cycles Renderer.