Currently attempting to reduce the overall texture memory of our aircraft by
using BC1/DXT1 compression for normals maps. Due to the extreme per-livery
variability of details on the A320 it is not possible for us to use decal
strips for fuselage details, instead we use 3x 8192^ for the fuselage. BC1 has
a very low signal-to-noise ratio when combined with the normal map scale
slider in the MSFS material options, and would save almost 250MB of texture
data across our aircraft with no visual quality loss. Unfortunately this is
not possible right now, as MSFS will not accept BC1 compression on normal
maps, only accepting BC5 signed. If I force BC1 compression the result is
heavily offset normal angles and odd motion-blur effects. Is this by design,
and if so, will it ever be possible to use a heavier, 4bpp, compression method
for normal maps? Thanks
Hello @FNX_Dave , Yes, it’s by design and we don’t plan to make any changes.
Ideally, you should use PNGs/Tiffs as input and let the compiler do the
conversion. Also, Be aware that you can use .flags :
here
Regards, Boris
Hi @Boris - Thank you for taking the time to reply to my query.
Unfortunately, following the SDK as linked is precisely the problem; it is
unnecessarily inflating texture memory by almost 600MB across the package
(when factoring in albedo/comp maps too) by offering no ability to set the
preferred compression methods. The flags file has only one option relating to
compression, and that forces BC7 - if QUALITYHIGH is not set, MSFS makes its
own choice of block compression format (that is often wrong), offering no
control to the artist. Would it be best for me to resubmit this as an idea?
There are many benefits to giving control of the compression method used to
the artist vs. letting the sim decide based on material slots.
Hi @FNX_Dave, You can submit this idea indeed but as Boris said we are not
planning to implement such a feature in the foreseeable future. Best regards,
Eric / Asobo
Hi Eric - Understood, thank you 