Choosing a strategy for rendering

Choosing a strategy for rendering

You have two possibilities: choosing a maximum render time limit (in minutes) or a maximum Samples Per Pixel (SPP) number, depending on your preferences.

If you are on a deadline, you will probably want to get the best quality image in a given time. For instance if you have around two hours you can enter “120” in the “Render phase time limit” field and 100000 in the “Samples Per Pixel” field. The render phase will then be interrupted after 2 hours, or after a SPP of 100000 is reached (which is not likely…).

Another strategy: you want to get to a Samples Per Pixel number of N (for instance N=5000), which you consider necessary and sufficient for your needs. In that case you could enter 120 minutes (the maximum time authorized) and 5000 in the SPP field. The render will then stop when the desired SPP is reached. You should always use this strategy when you render an animation, to ensure that all frames are of the same quality.

If you are not too sure, for instance you would like a SPP of 5000 but it is not mandatory, and in any case you do not want to exceed a 1 hour render phase time, you would enter “60” and “5000”. In that case the render phase will be stopped as soon as the 60 minutes limit is reached, OR an SPP of 5000 is reached.

Please note that the total time of a project includes several factors (the example below is for a cooperative project):

  • The time needed to send the scene to all the nodes. This is quick, generally less than one minute with most scenes, and several minutes with complex scenes.
  • The render time (the longest part obviously, which you specify the length in the Submit Project form). Please note that Indigo does not stop exactly when the time limit specified is reached: a small amount of time (a few seconds to a few minutes) is always added to allow for post-processing, saving the IGI file, etc.
  • The time needed to gather and merge all the IGIs across the network into the final IGI. It depends on the IGI sizes (see next paragraph).
  • The time to create your temporary ftp account and transfert the files (typically less than one minute).

Warning: We recommend you use the cost estimator on the RANCH web site to better estimate the total cost of your project first.

Important: IGI size and processing time

The final IGI file is obtained by gathering and merging the cooperative IGI files from all the RANCH Runner nodes. The size of a IGI file depends mostly on the resolution of the project. The gathering time (copying all the IGIs across the network) and the merging time (the fusion of all these IGIs into the final IGI) depend on the size of each IGI.

With very large IGIs, a huge amount of data must be transferred back and forth across the network, and the time required for the gathering + merging phase can be quite long. That being said, the RANCH Runner offers the highest level of merging performance available today. The current individual IGI size limit that can be processed with our parallel multi-merging technique is around 5 GB.

  • The gathering+merging phase takes 4 to 5 minutes with 1 GB IGI files (around 200 MB per minute).
  • After the merging, the tonemapping typically takes from a few seconds to one minute.

Files produced by the render

If your project is a still image / cooperative render

You will find in the ftp directory of your project:

  • your original .VUI file.
  • the final IGI merged after the cooperative render.
  • a final tonemapped PNG image of your project (with the suffix “_final”).
  • a “denoised” version of the final image (with the suffix “_denoised”). The final image file is automatically filtered at the end of the RANCH process in an attempt to reduce the amount of digital noise in the picture.

Note 1 : the effects of the “denoising” are subtle. It will never replace a longer render time, and it will never transform a supergrainy image in a perfect image , but it can help to “clean” the final picture by removing some of the noise. The denoising pass is very fast and done at no extra cost for the customer.

Note 2 : on some images the denoiser may fail. In that case the “_denoised” image will not be present in the directory. As it is an automated process, the denoising phase cannot be as refined as if you had denoised the image manually, and in some circumstances it won’t work. Please consider this feature as a bonus free of charge, not as a guaranteed result.

If your project is an animation

You will find in the ftp directory of your project:

  • your original .VUI file.
  • all the frames of your animation in PNG format.