In computing at least, "rendering" means "drawing", and "visualisation" is the process of drawing a picture of data, so the terms "rendering" and "visualisation" are fairly interchangeable.
First, lets look at the two main types of rendering:
In this video, we see:
- Contouring, drawing round objects of interest, labelling pixels, resulting in a segmented region.
- Converting segmented regions into triangle meshes.
- Reducing the numbers of triangles, to ensure rendering is fast enough.
- Rendering such a surface, as a solid surface or as wireframe.
In this video, we see how volume rendering is different to surface rendering:
- Volume rendering works on voxel data directly.
- There is no explicit segmentation step.
- The value of a pixel in the image is determined by what a ray of light travels through, and functions that map 3D image (e.g. MR/CT) intensity or gradient to opacity and colour.
You can also mix surface rendering and volume rendering: