As an alpha-tester I think the first thing to test is if the program can correctly do some elementary tasks.
So I've made a terrain 4097×4097 with GeoControl, I've named it "020Geo_06-12-20_21h12.ter" (later on I simplified the name as "GC247_aabc.ter", but it's the same terrain file)
I've uploaded this terrain in Terragen 2 v1.8.56.2
I've choosen very elementary settings ("GC247_aabc_012.tgd") for a Full Render 2048 × 1536 pixels.
I've named this render "GC247_aabc_012_3h32m19s_9442444_micro-triangles.bmp", because the render Time was 3:32:19 for 9,442,444 micro-triangles.
When I scrupulously examine the obtained image in my Photoshop (fig. 00 only shows a 35% reduced view of the render), there are numerous defects, probably coming from some bugs in the program:
1. numerous whitish spots in shadowed areas, some of them visible even without zooming (some examples on fig. 01)
2. other strange things (fig. 02 is a 50% view in Photoshop) :
— of which the most strange is perhaps the arch seen on a 400% view (fig. 03, #3)
— fig. 04 is a 200% view of a strange overhang near a flat horizontal zone (#2)
— fig. 05 is a 500% view of an antialiasing problem (#1)
— fig. 06 is a 400% view of 2 strange nearly square light zones, principally the lower one (#4)
— fig. 07 is a 300% view of strange chinese or hieroglyphic character in a shadow zone (#5)
I've send to Matt in a private email
— the address for downloading the terrain (*.ter), the *.tgd and the *.bmp files