Is there a way to predict rendering times? In purpose of load balancing I need to approximatively predict rendering time my graphics software (in the specific case it's Autodesk Maya) needs to render a task given an input file (.ma/.mb) and rendering parameters. 


An intuitive way to do it is to render several frames from different parts of a scene and to extrapolate the results. Is there a better way to do it? 
If no, is it enough to render several separated frames or I should take short series of frames in different moments of the scene?
You can predict it using Machine Larning / Data Mining algorithms, provided you have prior knowledge of the data. In your case,you should know the rendering time from previous experiments.


You can use any predition models. Some of them like bayesian models gives high accuracy prediction,but are computationally complex. Statistical models are very fast,but the provide less accurate results. You can use decision tree based models for a balanced performance.
CART algorithms is a good one. Use any datamining tools like weka,Rstudio or rapidminer to make the job easy.