2. The two phases system

PresenZ generates images through a two-phase system consisting of a detection phase and a render phase. Once these two phases are complete, the PresenZ Merger combines the results to create a “.PRZ” file that can be used by the PresenZ viewer.

Note

Technically, as far as V-Ray 3ds Max is concerned, both phases are two or more renders.

• Detection Phase

During the detection phase, PresenZ gathers all the necessary information to cover whatever is visible from the ZOV, optimizing this information to obtain the proper detail level as seen from the ZOV. This phase probes the 3D scene to define what render origins and directions have to be performed during the next phase (the render phase).

At the end of the detection render, PresenZ generates a “.przDetect” file that is stored in the przDetect subfolder created automatically at your output render pass.

Note

Depending on the render engine, there might be multiple detect passes, for example, one for transparent and one for opaque objects.

• Render Phase

In the render phase, PresenZ shoots sampling rays according to the origin and direction given by the detection phase. This phase applies lighting and shading, resulting in color data and other AOVs (Arbitrary Output Variables) computations for the final output. The render phase generates a “.przRender” file that is stored in the przRender subfolder created automatically at your output render pass.

The “.przRender” file is a RAW PresenZ image file that contains all the color and AOV information in half float precision. This file can be manipulated for color calibration and compositing and supports both V-Ray color correction and OCIO (OpenColorIO).

• PresenZ Merger

Finally, the PresenZ Merger converts the previously created “.przRender” file(s) to a “.PRZ” image file that can be directly displayed by the PresenZ viewer. The .przRender files carry uncompressed pixel data, which is compressed during the merging process, resulting in a smaller file size that can be easily handled by the viewer.

In summary, PresenZ uses a two-phase system to generate images for the PresenZ viewer. The detection phase gathers information on what is visible from the ZOV, while the render phase applies lighting and shading to create color data and other output variables. The PresenZ Merger combines these two phases to create a final “.PRZ” file that can be viewed in the PresenZ viewer.