POV-Ray 3.7

POV-Ray is an SDL based (Scene Description Language) render engine with a long history that makes it very stable and feature rich. The latest version of POV-Ray 3.7 can be found at the project site.

Features

Some key features of the exporter include:

Geometry import and export with their modifiers, keyed and physics animation
Add POV-Ray specific non-mesh primitives (never show tessellation)
Instances
Hair particles
Smoke simulations
Atmospheric media (volume fog)
HDRI environment mapping
Aperture depth of field
Material properties such as filtering, emission, translucency, subsurface scattering, glass fog (tinted absorption), blurry/glossy reflections…
Procedural textures (emulated from Blender and POV-Ray native)
Image textures
Texture influence channels: Alpha, Diffuse, Bump, Specular, Mirror (uses same channel as specular)
Global illumination: Radiosity (indirect lighting), photons caustics (reflect/refract), mesh lights
Custom POV-Ray code input giving access to any POV-Ray feature not supported by the exporter.

POV-Ray 3.7 features

Volumetrics and media (scattering/absorption), blurry reflections (uberPOV), ghosting for motion blur (uberPOV), micropolygon displacement (HGPOV), etc.

Activation

Of course, don’t forget to download and install POV-Ray itself!
Open Blender and go to Preferences then the Add-ons tab.
Click Render then POV-3.7 to enable the script.

Nutzung

Quick Start

Choose POV-Ray 3.7 from render engine selector. Then you can render as usual with the Render button.
The image will be rendered according to parameters set in the Properties.

Main global render settings for instance can be changed in the Render tab. But there are also properties for environment, material (textures), object, etc. all accessible in other tabs depending on the selected object (geometry, camera, light…).

POV-Ray Branches

Below is a comparison of some features of the two engines available to this exporter:

Feature/Engine/Support	POV-Ray	UberPOV
Full Spectral Resolution	✗	✓ (under development)
Supersampling	✓	✓
Alpha Mapping	✓	✓
Bump Mapping	✓	✓
Normal Mapping	✗	✗
Displacement Mapping	✗	✗
Motion Blur	✗	✓
Subsurface Scattering (SSS)	✓	✓
Volumetric Scattering (Medium)	✓	✓
Blurred Reflections	✓ (very tricky)	✓
Clay Render	✓	✓
Depth of Field	✓	✓
Material Layering	✓	✓
Thin Film Coating	✓	✓
Dispersion	✓	✓
Anisotropy	✗	✗
Thin Film Interference	✓	✓
Complex IOR Files	✗	✗
Coating Thickness Absorption	✓	✓
Custom Reflectance 90	✓	✓
Custom Fresnel Curve	✓ (tricky)	✓ (tricky)
Sigma Texture	✓	✓
Sun-Pool Caustics	✓	✓
Ambient Occlusion	✗ (tricky)	✓ (under development)
Lens Shift	✓	✓
Diaphragm Circular/Polygonal	✓	✓
Per-Object Texture Coordinates	✓	✓
Texture Projection Modes	✓	✓
Front/Camera Mapping	✓ (tricky)	✓ (tricky)
Multiple UV Channels	✗	✗
Texture Tone Mapping	✓ (tricky)	✓ (tricky)
Procedural Textures	✓	✓
Texture Layering	✓	✓
Synthesis Texture Layering	✓	✓
Point Lighting	✓	✓
Mesh Lighting	✓	✓
Image-based Lighting	✓	✓
Physical Sun/Sky	✓ (tricky)	✓ (tricky)
HDRI Support	✓	✓
IES Texture Support	✗	✗
Instance Support	✓	✓
Resume/Merge Render	✓	✓
Interactive Render	✓	✓
Vignetting / Bloom / Glare (Post)	✓ (tricky)	✓ (tricky)
Camera Response Function (CRF) (Post)	✗	✗
Color Balance (Post)	✗	✗
Multithreading	✓	✓
Region Rendering	✓	✓
Passive Emitter	✓	✓
Invisible Emitter	✓	✓
Invisible Object	✓	✓
Shadowless Object	✓	✓
Shadowless Point Lights	✓	✓
Bucket Rendering	✓	✓

Exported UI Properties

Render Properties

Radiosity

In POV-Ray, „Radiosity“ is diffuse interreflection which has nothing to do with vertex color based radiosity. In fact, it is more similar to final gathering of irradiance samples and provides a noise free indirect light.

Some presets to radiosity are included, their names and settings are those of the rad_def include file shipped with POV-Ray, they set up the properties so you don’t need to include the rad_def.inc in the exported pov-file, it’s one of the many examples of what an interface like Blender can bring to all POV-Ray users who are not used to have one.

Siehe auch

More details on POV-Ray Wiki.

Anti-Aliasing

Three sampling methods are supported:

Non-recursive
Recursive
Stochastic (Monte Carlo) Only available for UberPOV.

Sampling Depth

Values must be comprised between 1 and 9. Higher values increase render time and may even introduce some undesired blur.

Anti-Alias Threshold

In the simple, non-recursive method, POV-Ray initially traces one ray per pixel. If the color of a pixel differs from its neighbors (to the left or above) by at least the set threshold value, then the pixel is supersampled by casting a given, fixed number of additional rays. The default threshold is 0.3 but it may be changed using this Antialias_Threshold=n.n option.

Siehe auch

More details on POV-Ray Wiki.

Tipp

Depth of Field Without Anti-Aliasing

Using no anti-aliasing when camera depth of field is on will speed up rendering and often provide decent enough images.

Bounding Method

Also called acceleration, it is set to automatic BSP (Binary Space Partitioning) by the exporter as it’s generally the most efficient (POV-Ray 3.7 only) but other acceleration methods are available in POV-Ray.

Siehe auch

More details on POV-Ray Wiki.

Command Line Switches

Some command line arguments can be passed to POV-Ray. Arguments are separated by spaces. Command line switches consist of a / (Slash), + (plus) or - (minus) sign, followed by one or more alphabetic characters and possibly a numeric value.

Siehe auch

More details on POV-Ray Wiki.

Some Commonly Used Commands:

-D: Hide image while rendering: Use this command line switch to not show the rendered image in POV-Ray (slightly faster and lighter on memory). The image will be sent back to Blender after completion (on Linux this is a hidden default switch to avoid OS-specific editor problems).
+WT: Limit the number of threads used: Limits POV-Ray to using only one single render thread. (Likewise, +WT2 would instruct POV-Ray to use two render threads.)
+C: Continue an interrupted render: For „Continue trace“ is able to recover the point at which your last render stopped and continue it from there (even if you switched off your computer).
/EXIT: Close POV-Ray after rendering the image: There is an option in POV-Ray for Windows interface to do the same: The „On Completion“ option to „Exit POV-Ray for Windows“ (in the Render menu).

Tipp

Fast Preview Renders

When first setting up your scene, and for fast preview rendering, turn off anti-aliasing, depth of field, photons, Radiosity, expensive material features, and in the scene Shading panel, turn off shadows. (Other features might get turned off from this panel in future versions of the exporter.)

Alternatively, use the Quality command line switches +q1 to +q11. These allow you to easily disable most of the CPU-intensive features.

Formatting

The exported POV-Ray file can be customized:

Different indentation characters to choose from.
Option to add comments to POV-Ray file.
Option to write long lists of coordinates in one line for easier browsing of the pov-file (and slightly faster parsing by the renderer).

Scene Properties

Color Management

sRGB is supposed to be always used currently.

World Properties

Background

Blender World gets exported:

As POV-Ray background{} if flat colored.
Using Blender’s Blend Sky options triggers its export as a POV-Ray sky_sphere{}.

(Sky texture currently appears a little different because of its mapping).

Atmospheric Media

(To create volume lights):

Number of samples for media calculation
Atmospheric media color

Object Properties

Importance Sampling

It is a priority value between 0 and 1 that can be set per object in the Object properties tab for Radiosity to cast more rays at objects that require them most. Touch this rather carefully when trying to improve render times.

Data Properties

The script exports sky, lights, hair particles, smoke, fluids, meshes, blobs (metaballs).

Camera

Depth of Field

It has to be enabled for below property to act:

The focal point of depth of field is based on Blender UI Distance field, or Object field.

Aperture

Sets the blur amount (increase to get more).

Perturbation

Normal map for camera plane, native POV procedural patterns can be used with variable:

Strength
Turbulence
Scale

Lights

No Shadows toggle button can be used to deactivate tracing of shadows for specific lights only.

Tipp

For Realistic Light Attenuation

Use Inverse square falloff, and a small falloff distance value with a higher light intensity will give the best results with POV-Ray’s implementation of inverse square law. See this discussion.

Smoke

A DF3-file (POV-Ray voxel format) is exported and used with a POV-Ray media container with the same dimension and resolution as Blender smoke domain.

Hair

A union of POV-Ray sphere_sweep is exported and used for each strand. They can take the color of a texture applied to emitting object, and shape of sphere sweep tries to emulate shape of strands.

Material Properties

Emission

Tipp

Mesh Lights

When used together with Radiosity, the Emit property will allow you to create light bulbs or any luminous form that really illuminates other objects.

SSS / SSLT

Note that SSS in POV-Ray (called SSLT) is very sensitive and will give different results if the mesh normals are smooth shaded or flat.

Translucency

Illumination from the back of a surface.

Siehe auch

More details on POV-Ray Wiki.

IOR Mirror

This option is for using one consistent IOR for ray-traced reflection and refraction and not breaking the law of conservation of energy between the two.

Iridescence

(Newton’s thin film coating.)

Caustics

Chromatic dispersion for refractive caustics
Fast fake caustics (somewhat like Blender Ray Transparency)
Refractive caustics using photons
Reflective caustics using photons (high IOR or no mirror IOR for easier effect.)

Tipp

Faster Photons

To set up some caustics, try moving from the smallest photon depth value to a minimum at which you start to see the effect you are after. Check off the Receive Photons object property for any object that does not really need it. (A glass object casting caustics often doesn’t need to receive any itself.) Then you can balance other parameters to tune photons distribution and smoothing (gathering). Don’t set the global spacing too fine in scene settings, because then you can still make it finer on each object using its spacing multiplier. If your system has several threads, they can be used in the photons stage: one thread per light, so you can then make your scene lighting more complex without overhead.

Shaders

Emulation is attempted from Blender for:

Specular and diffuse toon (no edges yet)
Phong and Cook Torrance (both the same)
Blinn (not perfectly matched)
Ward isotropic
Fresnel and Minnaert, started but not finished yet

Tipp

Glass Like Materials

When trying to achieve some glass like material, keep low diffuse value, dark or totally black to avoid a dull surface and keep a clear transparency.

Texture Properties

UV Coordinates

Best with planar projection for now. (Silvio Falcinelli)

Texture Channels

Texture influences currently exported are: Alpha, Diffuse, Bump, Specular, Mirror (uses same channel as specular). (No other channel because of POV-Ray non-uniform syntax for them.)

Custom Gamma

For image textures (read POV-Ray 3.7 docs before using since it generally needs not be used).

Siehe auch

More details on POV-Ray Wiki.

Custom POV Code

POV-Ray files are not just pure data files (unlike with most other renderers). They are programs, with loops, functions, etc. This means that no matter how many features this exporter could support, POV-Ray will always have much more under the hood.

Step by Step

You can add custom POV code directly in Blender’s Text editor, all you have to do is to make sure this POV code has directly or indirectly a #declare keyword, followed by the name of your choice and the POV item you want to use. (Current POV syntax is closer to C than Python, so anything that follows two slash character (//) is a comment.)

Adding POV Code Directly

POV items can be anything but for now only the equivalent of Blender materials can be replaced with this method. In POV-Ray, it is called texture {} don’t get confused, it really includes all the material properties.

Though you can directly specify a texture {} block in POV-Ray files, the #declare directive allows to assign it to a variable and reuse it more easily. The exporter makes use of this feature by default, so you won’t be able to use your custom texture, unless you declare it. Here is an example:

#declare MyTexture =
texture{
    pigment{
        brick color rgb< 0.99, 0.99, 0.99>  // color mortar
        color rgb< 0.75, 0.5, 0.30>*0.75  // color brick
        brick_size <0.25, 0.0525, 0.125> // format in X, Y and Z-direction
        mortar 0.01                      // size of the mortar
        scale 3
    } // end of pigment
    normal {wrinkles 0.75 scale 0.01}
    finish {ambient 0.15 diffuse 0.95 phong 0.2}
    rotate<0,0,0>  translate< 0.01, 0.00, 0.00>
} // end of texture

Open the Text editor’s Sidebar.
In the text view properties option, you can chose to render 3D View and/or text. Enable Both.
Syntax highlight detects pov/inc/mcr/ini extensions.
Some complete POV-Ray scenes are available to Templates header menu.
And an Insert menu to add just some POV code snippets at cursor’s location.
Then you have to go into the material properties to the Custom POV Code field, and just type in the name of your declared item to use: „MyTexture“ in the example given. Then you can render your image normally and the material will be replaced.

Blender and POV-Ray do not have the same coordinates systems: POV is Y up while Blender is Z up, so it is to be expected that text generated content is not turned the same as exported UI items since the exporter adds a transform matrix to all exported entities. So if you want to specify orientations more intuitively by looking at the interface, some transforms have to be specified at the end of your custom blocks, for instance as follows:

scale <-1, 1, 1>
rotate <90, 0, -90>
}

Adding POV Code from Include Files

In any POV-Ray scene you can use the #include directive to add items from an external POV-Ray file. It’s like the import function in Python. The files to be included have .inc as their name extension. Then in the replacement field, you can type in any of the declared names available in the include file. „Out of the box“, POV-Ray ships with a lot of include files. So you can use them for your textures, but you can also use them for some of their elements. For instance a very often used include file is one that allows to call colors by their names instead of numbers called colors.inc, so the previous example could also be written:

#include "colors.inc"
#declare MyTexture =
texture{
    pigment{
        brick color White*0.99  // color mortar
        color rgb< 0.75, 0.5, 0.30>*0.75  // color brick
        brick_size <0.25, 0.0525, 0.125> // format in x, y and z- direction
        mortar 0.01                      // size of the mortar
        scale 3
    } // end of pigment
    normal {wrinkles 0.75 scale 0.01}
    finish {ambient 0.15 diffuse 0.95 phong 0.2}
    rotate<0,0,0>  translate< 0.01, 0.00, 0.00>
} // end of texture

More details on POV-Ray Wiki.

Isosurface Box: An isosurface component shaped as a box.
Isosurface Sphere: An isosurface component shaped as a sphere.
Supertorus: An isosurface shaped as a torus with deforming parameters equivalent to those of the superellipsoid.

Parameters (POV-Ray names):

MajorRadius, MinorRadius: Base radii for the torus.
MajorControl, MinorControl: Controls for the roundness of the supertorus. Use numbers in the range [0, 1].
Accuracy: The accuracy parameter.
MaxGradient: The max_gradient parameter.

Macro Based Primitives

Two primitives are actually macros that generate a mesh from curves before render time:

Polygon to Circle Blending
Loft

Importing POV-Ray Files

From the same Add menu, you can also import POV-Ray files.
Or otherwise, clicking File ‣ Import from the Topbar menu.
You can then select one or several files.

Referenz

Kategorie: Rendern
Beschreibung: POV-Ray 3.7 integration for Blender.
Ort: Render ‣ Engine ‣ POV-Ray 3.7
Datei: render_povray folder
Autor: Campbell Barton, Maurice Raybaud, Leonid Desyatkov, Bastien Montagne, Constantin Rahn, Silvio Falcinelli
Lizenz: *GPL*
Beachte: Dieses Add-on ist gebündelt mit Blender.