The circle moves from left to right of the screen during two seconds in a linear movement (constant speed). Images are rendered for only one frame at time=1s so there is a motion blur visible. The three examples of subsampling factor are just displaced in the x coordinate as a group.
Subsampling factor amount start and end only works for Linear. I’ve discovered that it has a bug (I think) because the ‘end’ factor doesn’t do anything apparently. No image for those parameters, they are just a shift to the left or right of the linear effect.
The images are rendered with the following settings:
Start time = 1s
End time =1s
Quality = 8
Antialiasing =1
By default, Synfig produces more subsamplings internally according to the quality (best quality more subsamples) and so, subsamples factor parameter is not noticeable at good quality at the final render for small apertures. For high apertures (like my previous laser example) it is mandatory to use that parameter. So in this case, I used quality = 8 to make visible the effect of the subsamples factor of the layer.
To make your thing brighter just increase amount of the thing over 1.0. It could be the amount of the shapes of the thing or the amount of the group of the things (included motion blur layer). Effect is the same.
-G