POV-Ray with Subdivision (POV-Sub)

Authors: Xiaobin Wu, Jianhua Fan
Newest version 0.03 ( Update List )
Last updated : Nov 22th, 2004

mesh2.pov subdivided

Introduction

This is an expansion of POV-Ray (Persistence of Vision Raytracer), a very popular (and free!) ray-tracing software. We enhanced the POV-Ray rendering kernel with subdivision surfaces (Loop's Scheme). With this expanded version, you can easily create high-quality ray-tracing images using smooth subdivision surfaces.

Learn more about Subdivision surfaces and Ray-tracing.

Download

Before you download, please read the copyright of POV-Ray and our copyright. You need to have a full version of POV-Ray (3.6) installed before you download the following file.

Executable (for Windows) (1321K) (v0.03)

Then copy the file bin/pvenginesub.exe into the bin/ sub-folder where POV-Ray is installed. (like C:\Program Files\POV-Ray for Windows v3.6\bin\). Executing the pvenginesub.exe will run POV-Ray with Subdivision.

Syntax and Examples

The mesh objects defined by mesh or mesh2 can be subdivided by adding the following syntax at the beginning:

mesh (or mesh2) {
subdivision{

substeps n // n=steps of subdivisions
[smooth on/off] // smooth or flat surface shading (default on)
[subcrease value] // set the crease value for the non-smooth edges
[discard_boundary] // discard the boundary triangles
[tolerance value] // set the tolerance for matching shared vertices (for mesh object), default=1e-6

}
vertex_list ...
...
}

The following examples are rendered using the POV-Ray with Subdivision.

Example 1 - flat and smooth shading

Original (source) n=1, flat (source) n=2, flat (source) n=3, flat (source)

n=1, smooth (source) n=2, smooth (source) n=3, smooth (source)

Example 2 - UV mapping

(note: the original mesh is from POV-Ray distribution: scenes/objects/mesh2.pov.)

Original (source) 1-Step (source) 2-Steps (source) 3-Steps (source)

Example 3 - Boundary options

Before subdivision After 2-step subdivisions $subdivision{substep 2 discard_boundary}$ same (with discard_boundary)

For more information about subdivision on the surface boundary, refer to subdivision literature such as:
Towards Hardware Implemention of Loop Subdivision. by S. Bischoff, L. Kobbelt and H-P. Seidel. in Proceedings of the 2000 SIGGRAPH/EUROGRAPHICS Workshop on Graphics Hardware

Example 4 - Mesh object

(note: the original mesh is from POV-Ray distribution: scenes/objects/chesmsh.pov.)

Before subdivision After 1-step subdivision After 2-step subdivision

Example 5 - Shadow line removed by Subdivision

Before subdivision (source) After 1-step subdivision (source)

click the above pictures to see the difference.

Example 6 - Creases

Note that crease value only has effects on sharp edges in the initial mesh.

Before subdivision (source) No crease value (source) crease = 0.5 (source) crease = 1.0 (source)

crease = 1.5 (source) crease = 2.0 (source) crease = 3.0 (source) crease = 4.0 (source)