Installing POV-Person

Prerequisites

In order to use POV-Person you will need:

• a version of the POV-Ray raytracing software (Version 3.5 or above)
• the POV-Person library files
• at least a rudimentary understanding of the concepts of raytracing and the POV-Ray Scene Definition Language (SDL)

The POV-Ray manual and sample files are likely to be sufficient to give you an understanding of the terminology used in this manual. Various tutorials are also available on the Internet that may better suit your needs. A Google search on 'povray tutorial' should lead you to a wealth of alternative tutorials.

Downloads

Installing POV-Ray

1. Download and run the POV-Ray installer for your operating system. Installation is normally straight forward. Installation instructions and help files are included with POV-Ray. Prebuilt installation programs are available for most Operating System e.g. Windows, Mac-OS and Unix (including Linux and Solaris).
   Source code is also available for download.
2. Render the default test image in POV-Ray to make sure that the installation was successful.

Installing POV-Person

1. Download the POV-Person library files (The files in the library consists largely of ASCII text files containing POV-Ray SDL).
2. If you downloaded a compressed POV-Person archive, extract the files from the archive.
3. Place the POV-Person library files into a directory accessible to POV-Ray. You can use the standard include directory e.g. "C:\Program Files\POV-Ray for Windows v3.6\include" or you can create a new directory and add a library path to POV-Ray (Look for "library paths" in the POV-Ray help index).
4. Open the POV-Person library file 'pp00example.pov' in POV-Ray.
5. Click .
6. If you see a sample image similar to the following image then congratulations on having successfully downloaded and installed POV-Person. Otherwise review the installation steps above.

Adding a figure to your scene

• The povperson.inc file contains the top level POVPerson macros which pull in other files as they are needed.
• The ppFigure macro adds a single figure (the 'alf' character) to the scene at the origin.

The general form of the ppFigure macro is:

More People

The ppUndef call shown above resets the different categories of control variables to ensure that parameters intended to define one person are not carried over onto the next person. The general form of the ppUndef macro is:

It is possible to pass 0's into the ppUndef macro to carry over specific groups of parameters. The consequences of doing this are not necessarily straight forward, so this is not recommended for novice users of POV-Person.

Crowd Control A crowd is simply a group of figures positioned on a surface. POV-Person provides two macros that are used together to generate a crowd. The ppCrowdPositions macro generates a more or less random set of positions on a surface of your choice and stores those positions in an array. The ppCrowd macro draws a figure at each of those positions. You can of course call the ppCrowdPositions macro on it's own to locate a series of points on a surface where you can then position other objects of your choice. You can also define an array of points yourself then call ppCrowd to position figures at those points.

The following example illustrates a simplified use of the crowd macros:

• The ppCrowdPositions macro is called with a single parameter to request 16 positions on the default surface, which is a square starting at the origin and stretching out 10 units into the positive x and 10 units into the positive z dimensions.
• In this case the number returned into the variable ppNumberOfActualPositions should be 16, as there shouldn't be any problem with fitting this number of positions comfortably onto the surface.
• An array called ppCrowdFigureList needs to be created to hold the range of figure definitions that will be used to form the members of the crowd.
• In this case only one object is defined and added to the first element of the array, which means that all of the figures in the crowd will be the same.
• The first parameter passed to the ppCrowd macro indicates which element of the position array to start from and the second indicates the number of positions to use.

The above example should give a result similar to the scene shown below.

The ppCrowdPositions macro is quite careful about the positions it adds to the array, avoiding that a position is too close to one that's already been defined and avoiding that the positions are too close to a dramatic change of height on the surface. To do this it generates a random position, checks its proximity to previously defined positions, then samples a few points on the surface nearby to see if there is a large change of height. These checks are parameter controlled to enable you to avoid creating 'overlapping' figures or figures standing too close to an edge.

The following example illustrates this:

By declaring ppCrowdPlatform before calling ppCrowdPositions the macro scans this object, looking for 6 suitable positions. As the object is a sphere, any positions towards the outside edge will be too steep to stand on and will be ignored. The macro therefore selects 6 positions close to the centre of the sphere. Note. If the radius of the sphere is reduced below about 2 units, then ppCrowdPositions will start to have difficulty in finding enough positions and is likely to return less than 6 positions. This time, ppCrowdFigureList is populated with 6 potentially different figures by using the random parameter in a number of positions on the ppFigure call. This example also introduces a couple of control variables that can be used to constrain the randomness used for orienting crowd members. By default, ppFigure generates a figure facing out over the positive z axis. The ppCrowd macro turns them randomly through anything up to 360 degrees about the y axis. The ppCrowdFigureMinRotation control variable tells the ppCrowd macro to rotate each figure by at least 150 degrees. The ppCrowdFigureMaxRotation control variable tells the ppCrowd macro not to rotate any figure by more than 210 degrees. This means that all figures will face roughly towards the -z axis.

Tip 1. To prevent ppCrowdPositions from choosing positions that are too close to any figures that you want to position manually, you can add those positions to the array before calling ppCrowdPositions, then call ppCrowd starting from the array index following those positions.

Tip 2. The surface object that you pass to ppCrowdPositions does not have to be rendered. In various circumstances it is convenient to pass a 'tailored' version of the surface that you are planning to render. For example, you can slice a section out of the surface you pass to ppCrowdPositions to prevent positions from being located in that region.

Because of the edge detection algorithm:

1. Parts of a surface with more edges (e.g. Steps) will attract less positions than parts of the surface that are clear of edges.
2. If there isn't enough space available to position the number of figures you specify then there is the potential for a macro of this type to loop indefinitely. To avoid this there is a parameter on the ppCrowdPositions macro to limit the number of attempts to find a position. The ppCrowdPositions macro therefore returns the number of positions actually defined, which, unless it runs into this problem should be the same as you requested.

The ppCrowdPositions macro can be called any number of times to add positions to the array. This can be used to compensate for a reduced number of hits on areas with a larger number of edges.

To keep render times to a minimum it is usual to render distant figures in less detail than figures close to the camera.

The following example illustrates a slightly more adventurous sequence of calls.

Animation

POV-Person therefore provides a set of tools to reduce the number of poses that need to be coded by hand.

The ppInterpolatePose macro enables you to code key poses and interpolate between them. A very simple example of this is illustrated in the ppanimation001.inc pose file which interpolates between the ppsitting.inc pose file and the ppstanding.inc pose file. The ppMirror macro enables you to mirror a set of joint position left to right. This enables some repetitive sequences to be generated with a very small number of manually defined pose files.

Several animation sequences have been defined as standard. To see an example load the pp00animationexample01.pov scene file and run the renderer with a command line option of +KFF30. This will generate 30 frames that will produce a complete walking sequence from the 4 manually defined key poses. The animated sequence is illustrate in the following image.

Note. POV-Ray produces a sequence of images. To animate the sequence you will need a seperate tool that chains the sequence of images together into an animated file format. The image above is an Animated GIF. Other common animation formats include MPEG and AVI.

As you will see from the pp00animationexample01.pov it doesn't take much to add an animated character to your scene file. The following lines of SDL are used to control and define the 'walking' animated figure:

For an explanation of the control variables and to learn how to define your own animations, see the animations section of this users guide.