Specular reflections are reflections of shiny surfaces (specular shader, such as Blinn or Phong). It's important to know there are three main types of reflections:ĭiffuse reflections are reflections of diffuse surfaces (diffuse shader, such as Lambert). Most render engines allow tweaking these different parameters, to optimize render speeds: if you're not interested in reflections, there's no need to spend costly calculations on them.īy default most render engines won't consider reflections of light. Other options are rays to determine reflections (reflecting objects) or refractions (transparent objects). A ray may be shot towards a light source to determine if the spot is lit or in shadow.

From there several possibilities may be evaluated. When a ray hits the first object it meets, the ray stops. With raytrace rendering, rays are typically cast from the camera, one for each pixel. Actually, the calculation is done in exactly the opposite way: from the camera to the object to the light. The downside is the performance: these calculations are costly.Īs the name already predicts, it traces a ray from its source in a certain direction until it reaches it's destination (or better: a destination), thereby determining the path of light from a light source to an object to the camera. It can give very accurate results and produce realistic images.

Ray tracing is a method to calculate the path light travels. When an image is rendered, this is done in a few basic steps. Instead it's more efficient to go from the camera to the object and then query the amount of light that gets to that specific patch on the object. You may see why a renderer works this way: it may take many light paths to be considered to get from the light source, via an object, to the exact position of the camera. This would typically be the direct light received by that surface. The renderer then determines the amount of light that is received by that patch of the surface.

This is covered in more detail in the Lighting section.įurthermore light isn't traced into the camera, but the render engine determines which objects (surfaces) are 'in sight' by looking through the camera. You'll need advanced render techniques to mimic this light behavior. First of all, basic rendering doesn't calculate all possible reflections (bounces) of light from all surfaces (which would be a nearly infinite number of light bounces). Rendering works in a similar way, but not quite in the same way. It 'bounces' of the surfaces until it finally reaches our eye. In the real world, light travels from lights to the objects we see.

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