Some of you have been confused over the Garbage fractal filter used by the Random fractal generator. This important filter plays a very important role and that is to eliminate garbage fractals created from randomly created fractals.
But some of you have unknowingly set some of the filter settings so ALL fractals are filtered out.
What is happening is that the program is rejecting the random fractals. The garbage filter uses several parameter settings to determine the amount of fractal rejection. It also rejects fractals when the image produced is mostly the background color.
Version FA 4.0.3 has changes to make it less confusing and to show you WHY a fractal has been rejected.
Troubleshooting Garbage Fractal Rejection
First step:
Turn off the Filter checkbox. This will show all of the random fractals and turns off the fractal rejection.
Case 1: If the random fractals now shown are either poor or uninteresting, that means the combination of variations you chose are not working well. Try a different combination of variations. You can click on one of the Variation Blends to get a better set of variations to work with.
Also some variation combinations produce a lot of uninteresting fractals but with a handful of good ones.Some of the predefined Variation Blends do this.
Case 2: The random fractals look good but they are being rejected. Turn on the Show Render Info checkbox. Now you will see the Fuse % and Retain % for each rejected fractal. Version 4.0.3 shows why the fractal was rejected.
Unfused Cutoff and Unretained Cutoff (or Min Fuse Cutoff / Min Retained Cutoff)
The two settings that are used for fractal rejection are: Unfused Cutoff and Unretained Cutoff. The default values are 25% and 10% respectively. These settings are found in the Random Generation Settings panel.
If the actual Fuse % is less than the Unfused Cutoff, the fractal will be rejected. If the actual Retain % is less than the Unretained Cutoff, the fractal will be rejected.
You may need to decrease one or both values so that fewer fractals are rejected.
If too many fractals are filtered out, the Unfused Cutoff and Unretained Cutoff settings on the Random Generator can be adjusted to tune the filter.
Use the Show Render Info checkbox on the Make New tab to see the Fuse and Retained percentages of the unfiltered random fractals.
Some Fractals Render Better on CPU than GPU — Need higher Render Quality at Preview quality levels
There are some fractals that do not render well with GPU at low quality settings. Those fractals need a higher render quality setting.
So for those fractals, they will not look good at render quality of 50, but will be good at say 200.
Some of the Lua scripts create fractals that need a higher preview render quality setting.
The quality for the Random Generator comes from the Grid Thumbnails quality in Preferences.
Rather than change the Grid Thumbnails quality in Preferences, use the Quality Adjust setting at the bottom of the Make New window. (Its default value is 1, which is 1X multiplier)
That is a multiplier. So if Grid Thumbnails Quality is 50.
A value of 1 on Quality Adjust means the random generator will use 1 X 50 = 50
A value of 4 on Quality Adjust means the random generator will use 4 X 50 = 200
The Variants Editor has the same Quality Adjust setting.
The Quality Adjust setting is saved in the fractal definition, so Quicklook will use it too. That is why it takes Quicklook longer to render.
GPU rendering is not as “random” as CPU rendering – which leads to slightly lower quality. You cannot see any difference at quality of 1000, but at quality 50 you can see a difference with a few fractals.