There is one exception to my "no" that isn't relevant to what you asked, but you may find useful later:
If you render and export to image sequences instead of movie files, then you can easily rerender just a specific set of frames---e.g., frames 0-99 if your changes are just in the first 100 frames of a 10,000-frame movie.
Rendering takes a long time in any post-production software. You need to get accustomed to that. If you aren't sure of a change, render and export a low-resolution test movie or just render and export the segment that you're interested in. These are among the many performance improvement tips here; performance improvement is more about working smarter than it is about tweaking hardware and settings.
1 person found this helpful
Depending on what's going on, you may be able to pre-render e.g. the background elements and substitute the layers for ther pre-rendered clip, but otherwise as Todd already said - no, there is no way to adaptively render something. Blending modes, 3D shading, obscuration and essentially anything that has multiple layers interact changes the source of the calculation, not just the result, so there is no reasonable way to predict what that result would be and have an adaptive spatila blending algorithm these cases. Of course you can still do so manualyl by defining masks/ mattes or working with limited regions and blending the results together again in a second pass, but that in itself may not be more computationally efficient and as I was trying to indicate, may affect the look...
Thanks Todd & Mylenium for the firm answer.
Ii was my wishful thinking & hope to way to shorten the rendering.
I remember when I was in University some 20 years ago, at that time was doing some programming language like Fortran (or was it Pascal or COBOL, can't remember) where we need to "compile" the file to get an obj file. (Though different but the process was somewhat similar), It was on Unix system & at that time there is a "MAKE" command where when it "compiles" the file to obj file, it detects the changes & thus speed up the compiling process.
I understand though this is totally different from rendering a movie ... was just hoping there is one ....