(#9)making a planet - continued "bump/normal maps "

[john Van Vliet]

----- Warning DO NOT use Photoshop's or the old Gimp plugin !!!! -----
----- They DO NOT make a normal map that can be mapped to a sphere !!!!! -----
SEE:
viewtopic.php?f=21&t=16608

a few things on bump maps
------ Bump maps ------
STEP #1
--- please do some reading about just WHAT a bump map is ---
--- and the difference from a "normal map" ---
--- Google is a GOOD resource and so is wikipedia ---
--- Please use them !!! ---
http://en.wikipedia.org/wiki/Bump_mapping
http://en.wikipedia.org/wiki/Normal_mapping
a very good photo example is in a blender tutorial
the photos are worth 1000 words
http://wiki.blender.org/index.php/Doc:M ... ormal_Maps
a "photo" - rendering -- Then a Black & White copy of The Earth
|
a Normapmap
|
a Bumpmap/HeightMap ( note this IS NOT just a copy of the photo )
|
--- example --


Celestia's "bumpmap" is a 8 bit GRAY only image and has ONLY 256 tones of gray
it IS NOT a desaturated rgb "pseudo-gray" 24 bit image
black ( #0) is the lowest point
white ( #255) is the highest point
If you do not start off with a 16 bit height map( and turn that into the texture) It is recommended NOT to use a HeightMap in a add on
-- there IS NO GOOD WAY of making one from a image

It is BETTER if there is NO height data available then do not just use a b&w copy( or color copy) of the planet map as a HeightMap
you can but the results ?? well lets just say not good . You can hand make a HeightMap .
An example would be this one i was working on a while back for Mimas

it is also possible to use a Fourier transform to make a "high pass" , there are many types of this
the gimp/Gmic " frequency splitting " or the OLD-SCHOOL subtract a blured copy from it's self and that is a "high-pass"

and in Nip2 a "butterfield" ring pass "

some screen shots - let the evidence speak for it's self -- all are the from the same bookmark

no HeightMap

and all shots below i used a gray blank image as the texture
hand painted

high pass- gimp

and using the Mimas map as the bump map


now i did stop working on the hand painted and it is no way near done
but the difference from using the texture as a bump map...

what i do is start with a high pass then use the "dodge/burn " tool to make the craters and ridges . This dose take time .

but using normal maps dose work better
for starters bump map has only 256 tones so only 256 different heights - and causes an image to have a stepped look
-- this is the hand painted 8 bit directly converted into a normal map using the "nms" in the celestia source --


now let's say you DO have a 16 bit gray image from:
http://www.ersdac.or.jp/GDEM/E/index.html
-- bob's post on celestialmatters --
http://forum.celestialmatters.org/viewtopic.php?t=217
http://eros.usgs.gov/#/Find_Data/Produc ... opo30_info
or from the fracplanet program or "planet" using the 16bit.col
the two programs i mentioned output in 16 bit UNSIGNED integer ( 0 to 65538) MSB
most ( if not all ) of the DEM's for the earth are in 16 bit SIGNED integer ( -32768 to +32768) MSB
http://pds-geosciences.wustl.edu/missions/mgs/mola.html is in 16 bit SIGNED integer MSB
the code for making a normal map using nm16.cpp in the tools in the source code USES 16 bit SIGNED integer as input
the OLD and i do mean very old moon topo map in in 16 bit UNSIGNED integer BUT is ALSO in MSB and a very odd ramp ( 32767 to 0 then 65538 to 32768 black is 32767 gray is 0 and white is 32768 )
http://pubs.usgs.gov/of/2006/1367/dems/Images_16B/
do some research on the two different formats and two different byte orders ( msb,lsb) , there is way too much on the net on this .So i am not going to post it here .

now if you do want to use the tools bob talks about in the above link
see:
http://forum.celestialmatters.org/viewforum.php?f=6
-- IMPORTANT --
AND fallow his rules on using his tools & the textures made by using his tools
t00fri also has some VERY VERY good how tos on using his tools .He also WANTS people to LEARN how to do this for them selves , and so do I .

---------

[john Van Vliet]

-- continued ---
-- 8 bit ONLY bump map - and CAN NOT be used in nms or nm16 or the normal map texture tools ---

well as has been stated by me and many others
" there is NO good way to make a bump map WITHOUT REAL height data "
And there are NO step by step instructions
EVERY map will be different requiring DIFFERENT THINGS to be done

"shape form shade " ???? can some what - requires a LOT of work
using "stereo pairs " to extrapolate the data can only work IF there are stereo images
see: Dr.Schenk's
http://stereomoons.blogspot.com/


now synthetic ones can be done that "look" mostly OK
They would contain NO real data for any real object , but...
now using something that will make a 16bit height map to begin with . Then colorizing that would still be best

the Open Source programs i have mentioned in the other tutorials do just that

but some people like to do the " Frankenstein " way --- cut / copy / paste
-- an earth like --
- for an example i am only going to do ONE island or continent and not a full map
a base image my level4 earth tx_11_9.png

-- the REAL earth topo data with the mask -

a mask made with the plasma2 gimp plugin ( set to be vert and horz tillable )

and the plasma image ( cam be used as the "BumpMap" )

and the masked bump from the plasma image


now the masked texture with some rivers and lakes
100%artificial
the rivers DO NOT match with the noise image
now for the sake of argument lets say you do not have a mask from plasma noise and ONLY just the image above ( and/or)
want to match up the rivers and lakes with the topo ( the noise image dose not YET )
to make something from that ONLY is a bit tricky and is 100% artistic

a few ways to do this
in this example i DO have the real data BUT the shores do not work well
they look like some VERY tall cliffs ( and NOT the white cliffs of Dover) but ones that are 5+ miles high
the shores need to have a px value NEAR to 0 ( sealevel is 0 )
recolor the plasma mask so that the mask is the same color as the shore and normalize the image
merge the two ( copy/paste the REAL on top of the noise)
and use the layer settings to "darken only " the one layer and you get this


-- NO real data and/ or NO plasma noise
I will be using the gimp Gmic plugin ( as in the other tutorials - what can i say i like it . i like the terminal version better though )
one of the many many many tools in gmic ( this can also be done in the terminal - bash , or mingw-bash on windows to make a 16 bit image )
the tool is " Contours / Distance Transform " for that the "water" needs to be white

set it to
value = 255
metric = Euler
normalization = normalize

to that use the "levels" to move the "gama" form 1 to ?? about 2 or 3 - your choice
then drop the contrast a bit
gama 2 and contrast -30

that is a bit WAY to harsh and needs a bit of " roughing up"
there are many different ways - be creative and experiment
overlaying a B&W copy of the texture on top of this ( 25%-50% transparent ? aprox) IF there are NO shadows in it
with some noise

the Gmic tool " curvature" on the texture ONLY then masked

and that merged with the distance

---------- the final image ----------
and a 100% full synthetic bumpmap


try different things , have fun and experiment

[Reiko]

Thanks for these!

[john Van Vliet]

-- note ---
will be adding to this

FIRST:
there is no real good way to make a Height map without REAL height data
Mostly it is best that if you do NOT have real height data then do not use a heightmap in celestia

SECOND :
there ARE no
point by point
step by step instructions
every image IS different and no two will work the same way

that said it is mostly possible to make something that mostly sort of / kind of / might / almost/ work
pay attention to the "weaseling out part " / kind of / might / almost/ work "
90% of the ones i have started i deleted and started over , only to delete that one also.

some planet types work better than others

With a water planet you can use a "distance" operation
http://en.wikipedia.org/wiki/Distance_transform
photo-example
http://code.google.com/p/nll/wiki/DistanceTransform
see post 2

a distance transform and a curvature transform was used for that island

this DOSE NOT work well on a rocky planet

Sometimes ( i repeat ONLY SOMETIMES ) can a multi-resolution hi-pass work on a rocky image
sometimes it looks " ?? ok "??
hipass a 512x256
hipas a 1024x512
hipass a 2048 x 1024
and enlarge the smaller ones after a slight blure to fit into the larger until all the small images are combined
512x256 > 2 px Gaussian blur > enlarge to 1024x512
mix 50%-50% with the 1024x512
use that image > add 2 px Gaussian blur > enlarge to 2048x1024
mix 50%-50% with the 2048x1024
and so on ....
images with shadows WILL NOT work well
example of a image that wiil NOT work well ( a crop from Mercury )

SHADOWS are public enemy NO.1
-- added the missing image that WAS here last night and is not now --
a hi-pass of the above image


--------------------------------------------------------------------------------------
something that would be a bit better ( Also a crop from Mercury )

WAY less shadows in this one
-- hi pass of above ---

sometimes subtracting a D.O.G.( difference of Gaussian) from the hipass ( subtraction is a math function ,you do subtract the image )

--- edit
odd half of this is missing ?
it was there last night now it is gone ??????
adding inline the missing parts

[john Van Vliet]

replacing the missing half of the above post with a new post

now the above Hi-Pass images do still NEED A LOT OF WORK YET
and example
The Moon
the REAL height data


now a generated image BUT one that LRO might have taken
an image with shading from the sunlight


and finally a hi-pass of the shaded image


now ask your self ??
will that even remotely look good
if the answer is NO ,then .......

[PlutonianEmpire]

Where is the "high-pass" option in Gimp? I've never been able to find it.

[john Van Vliet]

for everyone reading this
PLEASE do some researcher
a "high pass"
means the HIGH frequencies PASS through
from google "high pass filter gimp"
second hit in the list
http://www.gimpusers.com/tutorials/highpass-masking
third hit in the list
http://www.gimp.org/tutorials/Sketch_Effect/