Celestia Forums

Being new to this game, this all a big learning experience for me.

My initial reaction to get the best image of Mars was to download the best images (textures) I could for it under the impression this would surely give me the best image.

Well judge for yourselves. Below is a combination of the standard 127k texture and an "enhanced" 283meg version. Both are then shown with and without a 45meg bump map.

To me at least the 45 meg bump map seems the best "value for money". The 283meg texture seems to offer next to no improvement?!

In each of the following examples, the first is the measly 127k texture, the second uses the whopping 283meg one...

Without bump maps



Now with bump maps



Without bump maps



Now with bump maps




So in my (noob) eyes it would seem best to get the best bump map possible and forget about the enhanced textures possibly? Seems the best use of disc space at least?

NeilF,
Wrong. The Bumpmaps or as most of us use Normalmaps now only give a simulation of elevation and usually it is the most noticeable from near the planets terminator ( shadow line ). The Mars textures you are showing pictures of have shadows already in the texture so it is not really giving you right idea. The texture shows the detail not the bumpmap. If a texture is only 4k and you use a 16k bumpmap you are still going to see the 4k texture. It will look now where as detailed as per say a 16k texture with a 16k bumpmap.
Let me show you some examples.

First here is a 4k Earth texture no bump


Next same texture with a 16k bumpmap


Next the 16k version of the texture with no bump


Next the same 16k texture with 16k bump


As you can see there is a big difference if you look at the coast lines and other inland areas. The lower the texture size the lower the detial the bigger the texture the higher the detail. It is all a matter of finding a balace of texture size and bumpmap size that your graphics card can handle and that you are happy with. I personaly say an 8k texture is the lowest I am willing to use for the Earth or Mars but I normaly use 16k textures of these with 16k normalmaps. Of course I have a GeForce FX 5900 so I can handle these textures. With a different card your millage may vary.

Don. Edwards

Thanks for the reply. Your post is very interesting.

Looking at the coast lines I can see your point. However, such features are rather rare throughout the solar system. If we look at Mars again, generally there is very little difference between using a 128k texture or a 283meg texture with a reasonable bumpmap - IMHO.

I take your point for a texture with definate detail - eg: earth with coast lines etc. But for most objects throught the solar system where such extreme contrasts in ground details don't exist to such a degree, it (IMHO) seem questionable to download textures using up hundreds of meg, when a bump map on a small texture gives such compariable results.

Did that make sense?

Unfortunately when I use a 8K bumpmap (or normal map) on my card (Radeon 9800XT) it get rather choppy, so I have to stick with 4K ones.

deleted

guest jo wrote:Sorry but after reading again and again I give up.
I don't know how you got the idea that a better resolution of textures doesn't show more detail.

In an ideal world you'd use the highest of everything... But... Here... Choose yourself...




The first example, uses 283meg, the second about 2.5meg... Is the first a 100 times better?

To me it seems a good bump map is far more important than hundreds of megs of textures... (at least for most planets) IMHO.

NeilF,

please do not forget that the more experienced users of this forum are
used to completely different levels of detail than what you display
above to underlign your point.

I have posted in the other thread a number of really hires Mars images
(that you chose to ignore!) .
http://www.shatters.net/forum/viewtopic.php?t=6980&start=10

That's what really matters. Please consider that many people
here, including myself, have made /very/ detailed studies of these
issues during the past three years! You could easily retrieve these
discussions through the search engine. As a long-term member of
Celestia core development, I think I really know what I am talking
about.

There is a very simple exercise you may try (all of this has been
discussed here widely before, of course). Just take a white empty
texture instead of the main Mars texture. Then you can study in
explicit detail what the bump-map does and WHAT NOT.

The amount of detail you can see is given by the resolution and
smoothness of the bump-or normal map. If you want lots of detail,
you need HUGE normal maps of great resolution and smoothness.

So there is NO tradeoff whatsoever.


Eventually, it's the lack of smoothness that will be the limiting factor
with normalmaps. This is due to the fact that normal vectors on a
surface are calculated by means of 'differentiation'. This is a


numerically very sensitive procedure...

We also had extensive discussions here among experts as to the
limitations of the DXT (dds) format in the context of normal maps.
Again the problem is the lack of smoothness in DXT.

Clearly, and ideally, we want /identical/ resolutions of all textures,
participating in the display of one 3d image.
In order to see detail, there is NO way past huge textures
with very high resolution. That's elementary physics...Nature cannot
be cheated

Ideally the main texture involves NO shading whatsoever, but it needs
to contain all the detailed i.e. hires shades of color which -- together
with the dynamical shading based on the bump-or normal map
-- make up the final 3d display.


Bye Fridger

t00fri wrote:NeilF,

please do not forget that the more experienced users of this forum are
used to completely different levels of detail than what you display
above to underlign your point.

I have posted in the other thread a number of really hires Mars images
(that you chose to ignore!) .
http://www.shatters.net/forum/viewtopic.php?t=6980&start=10

That's what really matters. Please consider that many people
here, including myself, have made /very/ detailed studies of these
issues during the past three years! You could easily retrieve these
discussions through the search engine. As a long-term member of
Celestia core development, I think I really know what I am talking
about.

Bye Fridger

You seem to be overlooking the purpose of my post. As a newcomer I have an uphill learning curve trying to work out what is worth downloading and what is worth doing etc. The complete exercise is a learning curve!

As I said before, my first gut feeling was to simply download the best definition texture I could - No doubt something virtually every new comer will do. In the case of Mars 283meg of it.

While impressive it barely (IMHO) gave the level of gain a small 2.2meg bump map gave.

Of course if you want to zoom closer and close to the surface to see the best detail you can then of course the higher quality the texture and the bump map the better. Clearly demonstrated by your lovely examples (which I did not ignore).

Please remember though (unlike yourself), a good many people using this package are not using it to the same degree/extent as you may be. These people cannot/will not probably wish to download 1 gig of data to display Mars for example. They are not after a definative render, but most likely the "best for the buck"! Hence my post/opinion.

Now of course, if you wish to continue to ridicule my simple conclusions, fair enough. I was simply trying to:-
a) Understand a complete new package.
b) Share my thoughts so other new comers would have something to compare against, and quite possibly in the process help them.

In my defense though, exhibit (a) and (b):-
(a) uses less than 3meg
(b) uses nearly on 300meg

(a)

(b)


I'm fairly sure which option would be best for giving a good "flavour" of Mars for a beginner or average user. (Refer to my previous example as well, about 1-2 pages up)

Oh,right.
But you are talking about a 127k texture map for Mars.And we still don??t have yet a complete 32k texture map of the planet.There is only one raw 32k texture.When we will have at least complete 32k texture maps for Mars?There are lots of images and information...
I would like to know if is there any advatange in putting a 32k Normalmap combined with a 16k texture map.Or putting 16k NormalMap instead of the 32k won??t make much difference?
I am talking about it because I don??t have a giant HD and I have to do the best I can with my not so big space

NeilF wrote:In my defense though, exhibit (a) and (b):-
(a) uses less than 3meg
(b) uses nearly on 300meg

NeilF,

you discovered one important thing in your studies: There are
300 Meg textures that are done worse and thus deliver
worse than other people's 3Meg ones!

On motherlode and elsewhere on the net you may find a lot
of crab (besides very good textures, of course)! So it's
important for everyone's 'learning curve' to concentrate on the
/signatures/ of what makes a good texture and what not.


This difference may seem trivial at first, but it really isn't.

For that reason, it's not a bad idea to be a little patient before
installing 500 Meg textures, notably /normal maps/.


Many texture 'creators' have never cared to learn even some
basics of image manipulation before submitting their first
texture. It is 'their learning experience' as you would probably
call it


One is always well advised to keep some names of people in
mind who really KNOW what they are doing at the texture
front!

Jestr or Don.Edwards for example are excellent
recommendations! I won't list the 'bad' guys now, but they are
known to some of us . In collaboration with a most
talented texture wizzard, Mario/Spacegraphics.com, I did
extensive studies of 'extreme' hi-end texture optimization in
the past. The (free) textures (Mars!) on his site are among
the very best available.


Since the quality of the normal map is the decisive factor for
the crispyness and 3d impression of the display, the
importance of it being smooth and of low-noise cannot
be over-emphasized. A hires normal map that you decide to
download, should by all means NOT be encoded as DXT1
format. DXT3 is a minimum quality requirement for /normal
maps/ in DXT format. The best bet for reasonably powerful
CPU+cards are PNG tiles, however! The quality difference to
any DXT encoding is immediately obvious, but DXTn is much
faster, of course....


The problem is that uploaders often don't even specify
whether they used DXT1 or DXT3 or even DXT5.

Unexperienced people like yourself then 'blindly' download
these 'monsters' and are badly disappointed about the
result...


An expert recognizes the answer immediately from the
/actual/ size of the texture compared to its nominal size (8k,
16k, 32k,...). The reason is the different inherent rates of
compression (8:1,4:1, 1:1,...)


I usually do the main texture in DXT1 (8:1) compression and
hardware decoding! That provides lots of SPEED reserve. But
for big size normal maps (>=16k), I always use PNG tiles.


...and so on....


Bye Fridger

PS: and by the way: as far as I can make out that dirt brown
Mars texture that you keep showing is a /flat/ one, NO
shading whatsover. Clearly that isn't fair to compare.

What you have to compare is a 'standard' 'statically' shaded
texture, corresponding to a /fixed/ location of the light source
(our Sun), to a /dynamically/ shaded one, where the shadows
change depending on the Sun's position! The latter is what
we all want and why we need normal maps or bump maps.

I believe you refer to space-graphics.com (not spacegraphics.com) ?

danielj wrote:Oh,right.
But you are talking about a 127k texture map for Mars.And
we still don??t have yet a complete 32k texture map of the
planet.There is only one raw 32k texture.When we will have
at least complete 32k texture maps for Mars?There are lots
of images and information...

I would like to know if is there any advatange in putting a
32k Normalmap combined with a 16k texture map.Or putting
16k NormalMap instead of the 32k won??t make much
difference?

I am talking about it because I don??t have a giant HD and I
have to do the best I can with my not so big space

Danielj,

forget the 127k. He simply did not yet know the standard
texture naming convention...There is NO 127k Mars texture.


Probably, he meant to refer to a Mars texture, the total size
of which is only 127KB... a "slight" difference


Bye Fridger

PS: An /excellent/ 16k normal map is all you need. Magnify it
highly. Inspect it...and then you will know easily whether it is
any good.

julesstoop wrote:I believe you refer to space-graphics.com (not spacegraphics.com) ?

Thanks! Of course I always /click/ his site from my bookmarks...

Bye Fridger

t00fri wrote:

NeilF wrote:In my defense though, exhibit (a) and (b):-
(a) uses less than 3meg
(b) uses nearly on 300meg

NeilF,

you discovered one important thing in your studies: There are
300 Meg textures that are done worse and thus deliver
worse than other people's 3Meg ones!

On motherlode and elsewhere on the net you may find a lot
of crab (besides very good textures, of course)! So it's
important for everyone's 'learning curve' to concentrate on the
/signatures/ of what makes a good texture and what not.


This difference may seem trivial at first, but it really isn't.

For that reason, it's not a bad idea to be a little patient before
installing 500 Meg textures, notably /normal maps/.

LOL!!

Well, maybe a sticky somewhere recomming a high qualilty texture/normal map, and a medium quality texture/normal map for some objects could be useful? ie: I'm obviously firing completely blind here, bouncing around making the same mistakes as no doubt countless others have made (& will make).

Regarding normal maps for Mars at least. There's only one to choice from on Motherload (for me anyway). 8K texture make my card (9800 RadeonXT ) slow right down. So I'm currently using the "VT Mars Normal Map" (500+meg). The surface texture is standard one, or the "VT Surface Map" by "John van Vilet".

Care to recommend alternatives

My next battles will be with the Moon and Earth... So again, I'll be trying to find the best downloads again... See where I'm coming from with a suggestions sticky?

Thanks again...

NeilF wrote:

t00fri wrote:

NeilF wrote:In my defense though, exhibit (a) and (b):-
(a) uses less than 3meg
(b) uses nearly on 300meg

NeilF,

you discovered one important thing in your studies: There are
300 Meg textures that are done worse and thus deliver
worse than other people's 3Meg ones!

On motherlode and elsewhere on the net you may find a lot
of crab (besides very good textures, of course)! So it's
important for everyone's 'learning curve' to concentrate on the
/signatures/ of what makes a good texture and what not.


This difference may seem trivial at first, but it really isn't.

For that reason, it's not a bad idea to be a little patient before
installing 500 Meg textures, notably /normal maps/.

LOL!!

Well, maybe a sticky somewhere recomming a high qualilty texture/normal map, and a medium quality texture/normal map for some objects could be useful? ie: I'm obviously firing completely blind here, bouncing around making the same mistakes as no doubt countless others have made (& will make).

Regarding normal maps for Mars at least. There's only one to choice from on Motherload (for me anyway). 8K texture make my card (9800 RadeonXT ) slow right down. So I'm currently using the "VT Mars Normal Map" (500+meg). The surface texture is standard one, or the "VT Surface Map" by "John van Vilet".

Care to recommend alternatives

My next battles will be with the Moon and Earth... So again, I'll be trying to find the best downloads again... See where I'm coming from with a suggestions sticky?

Thanks again...

There was actually extensive 'brainstorming' going on recently
concerning some sort of practical texture refereeing scheme
for the Motherlode. There already exists the possibility for
people to (anonymously) judge the textures and attach
corresponding labels. Personally, I am strongly opposed to
this scenario , like I also don't want to have books (that I
consider buying) judged at Amazon.com by anonymous
illiterates;-) .


My suggestion for mars would be to download Mario's 16k
Mars textures /and/ matched 16k bump maps. Although the
ones available for free download are in lossy JPG format, his
textures are great even in JPG format. Then you will have to
offset the texture by 'width/2' with any image manipulation
program to match the Celestia convention. You can also have
a try of my redmars8k at my TextureFoundry site


http://www.shatters.net/~t00fri/texfoundry.php4

The textures are not new, and also need a width/2 offset, but
they are very good given their 8k size. There are also
matched bumpmaps for download.


As I mentioned: anything bigger or equal to 16k should be
chopped into tiles. There is only one dedicated script for this
job: my 'virtualtex'.


Bye Fridger

Couple of problems here:-

a) Cannot find any (16K) textures by "Mario".
b) I have Photoshop and Painshop pro. Can these "offset the texture by width/2". What does this actually mean in English?
c) Regarding your "virtualtex", is there any documentation/examples? I've searched the forum and the only thing I've found is (http://www.shatters.net/forum/viewtopic.php?t=3089&highlight=virtualtex), which given I know nothing about "ImageMagick", and little more about the textures Celestia uses unfortunately doesn't help me much.

ie: Can I just download the 16K textures, and easily convert them to tiles?

Thanks

NeilF wrote:Couple of problems here:-

a) Cannot find any (16K) textures by "Mario".
b) I have Photoshop and Painshop pro. Can these "offset the texture by width/2". What does this actually mean in English?
c) Regarding your "virtualtex", is there any documentation/examples? I've searched the forum and the only thing I've found is (http://www.shatters.net/forum/viewtopic.php?t=3089&highlight=virtualtex), which given I know nothing about "ImageMagick", and little more about the textures Celestia uses unfortunately doesn't help me much.

ie: Can I just download the 16K textures, and easily convert them to tiles?

Thanks

(a) Indeed, he offers now only the 8k mars textures for download, but if you write him a friendly email, say hello from Celestia and myself, I am sure he will let you download the 16k (perhaps even in lossless tiff format). I assume you located his site. [He (and I) have Mars textures + matching Normal maps up to 46k...]

(b) I made a very precise statement before. The point is where the central meridian for the texture is to be located. The actual Celestia versions want it shifted by 180 degrees relative to Mario's convention or the older Celestia conventions. Since the cylindrical projections display 360 degrees of longitude in a texture of width =w, a 180 degree offset in longitude amounts to offset by an amount w/2 in pixels. If your texture has width=8192 pix, then you go to photoshop->filters->others->offset, enter 4096 into the x slot and make sure that 'warped' is activated.

After paying all this money for an expensive commercial program like photoshop, it would perhaps be a good idea to learn some basics of how to use that expensive stuff . You sure don't want to say that you snatched PS from somewhere?

(c) Just use the search engine. I am too busy to further enhance your 'learning curve' here .

/Many/ people managed to use it before you...

You wrote that you are a programmer by profession. So just look at the shell code. You should be able to read it like a newspaper. You can also just call it without arguments, then a brief help is printed:

It looks like this


So, suppose you got a 16k PNG texture, and want to chop it into 1024 pix sized tiles in PNG format, just type at the prompt:

> virtualtex <16k-texture.png> 1024 png

You have to repeat this procedure , of course, with all the other required textures that are smaller by factors 2^n. There are plenty of respective explanations available in the forum. The associated 8k,4k,... textures you just rescale trivially (with /bicubic mode!!) in photoshop from your biggest 16k texture.

Since the DOS- shell grammar is too stupid for that task, I had to write 'virtualtex' for advanced UNIX/Linux shells like zsh or bash. So you got to install a CYGWIN linux layer under Windows to have it run. I suppose you know what CYGWIN is. It's very easy to install. This should be extremely easy with your professional knowledge...You also need to install ImageMagick. It is free and exists for native windows, Cygwin-Linux and native Linux.


Good luck,

Bye Fridger

t00fri wrote:[He (and I) have Mars textures + matching Normal maps up to 46k...]

arrgghhh.... want them....
(crying baby in deep depression...)

No I'am kidding, I won't ask for them...

...

please?

ElChristou wrote:

t00fri wrote:[He (and I) have Mars textures + matching Normal maps up to 46k...]

arrgghhh.... want them....
(crying baby in deep depression...)

No I'am kidding, I won't ask for them...

...

please?

Well these are Marios "commercial" files, each texture being almost 3GB in size!! So with /asymmetric/ ADSL lines, /uploading/ is impossible, clearly.

Also you need special computer setups to be able to load such monster textures into memory to make changes. I have 3GB of CL2 RAM, for example and a fast 3.2 GHz P4 machine with a top-speed HD. So does Mario...

Notably also the 48k specular textures of Earth are incredible. You can see the sun reflect beautifully in small rivers and tiny lakes etc.

We have spent a considerable amount of joint research in exploring ways to make the normal (bump) maps optimally smooth and free of NOISE. For that purpose, one has to start from the /original/ 16bit level maps and do the 8bit truncation (required by Celestia) only as the /last step/ in the chain of image manipulation steps. Chris' 'nm16' normal map converter directly takes those scientific 16bit RAW level maps as input. I.e. altitudes are not encoded in 256 steps (8bit), but rather in 65536 steps (16bit). So the altitude patterns are incredibly more smooth, of course.

Another procedure that we explored to reduce the noise, was to stack many textures with random noise injected on top of each other in various modes (multiply,....). This technique is well proven in astronomical CCD or video photography. The stacking technique can enormously enhance the signal to noise ratio!

Bye Fridger

yes I forgot the spacegraphics.com is semi-commercial... and yes I know my poor computer will never handle such files...
But are the 8k maps (I don't remember if they was 8 or 16k...) at spacegraphics coming from those big ones?
In fact I just want to know if it's possible to do better 8k mars map or not...

Also those maps if I remember have a different offset from those from Celestia package... Is there a special reason for this?

Why this Mario is not anymore present on the forum?

ElChristou wrote:yes I forgot the spacegraphics.com is semi-commercial... and yes I know my poor computer will never handle such files...
But are the 8k maps (I don't remember if they was 8 or 16k...) at spacegraphics coming from those big ones?
In fact I just want to know if it's possible to do better 8k mars map or not...

Also those maps if I remember have a different offset from those from Celestia package... Is there a special reason for this?

Why this Mario is not anymore present on the forum?

It's now 8k as I learned yesterday, it was 16k before. And it's JPG not lossless TIFF. Yes, these 8k textures are /highest quality/ rescalings from the 46k textures! But my 8k Mars-map on the TextureFoundry is also pretty good . I think from the quality point of view these 8k maps are about the optimum one may do.

As to the offset, see under point (b) in my post a little higher up:
http://www.shatters.net/forum/viewtopic.php?t=6988&start=15

Mario spends most of his spare time in making such exciting monster textures...hence, not much time for chatting left . But he is very supportive towards Celestia. I think everyone will get bigger and better versions of his textures on friendly demand!

Bye Fridger