Celestia Forums

Ok, I have the cloud texture as JPG, Photoshop open... how do I make it be transparent?

ar81 wrote:Ok, I have the cloud texture as JPG, Photoshop open... how do I make it be transparent?

You add transparency like one always does in image manipulation (in which you are presumably an expert?)

But JPG does'nt work, since you need to add a standard ALPHA layer (white = opaque, black = transparent) to the RGB cloud texture. JPG's don't support alpha layers as you will probably know. Also JPG is a lossy format and thus NOT to be used during actual image manipulations!

A very good and most simple start is to just take the grayscale cloud texture as an alpha layer (possibly inverted!)

You must use PNG format or DXT3 format (DDS ending).
DXT1 again does NOT work for similar reasons as JPG.
In order to work with the hardware supported DXT format, you need a Photoshop plugin from NVIDIA's developer site...Again DXT1,3,.. is lossy and thus should only be converted into AT THE VERY END.

By using the forum's search engine, you'll find all these issues repeated here /several times/ ...

Bye Fridger

The software I use normally is not Photoshop.
I have never worked transparency, at most I have composed layers and I have colored comics.
I'm not expert. I have made stuff with primitive tools at hand.

May be that's why I got impressed with Celestia. Celestia is state of the art, and definitely NOT primitive.

ar81 wrote:The software I use normally is not Photoshop.
I have never worked transparency, at most I have composed layers and I have colored comics.
I'm not expert. I have made stuff with primitive tools at hand.

May be that's why I got impressed with Celestia. Celestia is state of the art, and definitely NOT primitive.

Then grab yourself a nice tutorial about image manipulation from the net. I recommend the GIMP tutorial. The gimp is rather similar to PS, but FREE of charge and exists for Linux and Windows. Many of us like it very much (certainly I like GIMP a lot ).

Bye Fridger

I guess I need to get working on the how to make cloudmaps tutorial.

t00fri wrote:Then grab yourself a nice tutorial about image manipulation from the net. I recommend the GIMP tutorial. The gimp is rather similar to PS, but FREE of charge and exists for Linux and Windows. Many of us like it very much (certainly I like GIMP a lot ).

Bye Fridger

Interesting. If you analyze, the real message is not an answer to the question. As I said I am a newbie in Celestia, and PNG transparency is often useful for games and software, not for printed material. So why should you expect me to know that?

My first thread was closed because there was some flame war. Now I ask for help and I get a "get a tutorial". If I knew that was teh answer I wouldn't bother to post here.

The point is such lack of warm atmosphere is not good for teamwork, let alone to motivate newcomers to make add-ons. If such a behavior is the common element here, Celestia is a dead project for an elite which might run out of help from contributors.

Don't take it personal, it is just how a newbie might see this place.

So what's your business? Is it to keep an elite? Or is it to get as many hands to help as possible. It's your decision, not mine.

I don't want this community to die, so I point out what I see,

The point is, that this is a forum about celestia in the first place.
Your question was related to basic techniques of image manipulation. As nobody on this forum can guess your level of experience, or even the software that you are using, it is a perfectly acceptable help to point you to tutorials: These tutorials are well written, probably much better than any forum member could. I really would encourage you to heed fridgers advice and take a look at The Gimp and its tutorials, there might be much more to learn that would prove helpful for (not only) texture creation for celestia.

steffens

ar81 wrote:

t00fri wrote:Then grab yourself a nice tutorial about image manipulation from the net. I recommend the GIMP tutorial. The gimp is rather similar to PS, but FREE of charge and exists for Linux and Windows. Many of us like it very much (certainly I like GIMP a lot ).

Bye Fridger

Interesting. If you analyze, the real message is not an answer to the question. As I said I am a newbie in Celestia, and PNG transparency is often useful for games and software, not for printed material. So why should you expect me to know that?

My first thread was closed because there was some flame war. Now I ask for help and I get a "get a tutorial". If I knew that was teh answer I wouldn't bother to post here.

The point is such lack of warm atmosphere is not good for teamwork, let alone to motivate newcomers to make add-ons. If such a behavior is the common element here, Celestia is a dead project for an elite which might run out of help from contributors.

Don't take it personal, it is just how a newbie might see this place.

So what's your business? Is it to keep an elite? Or is it to get as many hands to help as possible. It's your decision, not mine.

I don't want this community to die, so I point out what I see,

Wait a second...

after your first reply above, it became quite obvious to me that you were lacking many of the fundamentals of image manipulation. Knowing about transparency and alpha channels is a /general/ concept of image manipulation not a special one related to a particular format like PNG.

I recommended the GIMP tutorial for you first, because

-- you definitely need some further general know how in image manipulation before going on with a speciiific and somewhat tricky specialized task like clouds!

I guess you want your new clouds to be good and exhibit some interesting novel features. That can only succeed if you acquire first a broader basis of image manipulation background. You also will need some knowhow in applying bumpmaps to your clouds. Again a standard /basic/ concept in this field. You must also practice first to get familiar with either PS or GIMP. Again Tutorials are an excellent means to do so.

My 2k clouds I made > 2 1/2 years ago have been used by many (most?) Celestia users for a long time. They are still available for download and as a "learning example" from my TextureFoundry site.

-- the GIMP tutorial is simply EXCELLENT with lots of practical illustrations. There are pedagogical discussions about transparency and further applications of alpha channels and more general masks.
There you learn about selection techniques, layers /and/ bump and displacement maps in case you don't know about the latter already. You also learn about exploiting a host of different filters.

What do you guess why I do know all these things since long?? It's definitely NOT to "sell" you GIMP or PS I usually pick some quiet time slot and /READ, learn and practice/ until I definitely understand...This simple recipe works for most people

There are also great online tutorials to be found at the GIMP site,
http://www.gimp.org.

This is all much better than what I could provide here in the short time I have available for such things.

If you want my previous explanations ==> search engine ( you might even go back as much as 3 years when I tought these things step by step to Don.Edwards, Rassilon and a group of others;-) ) . That's why this forum HAS an excellent search engine...

Apparently you were rather seeking some kind of "cooking recipe" of how to make clouds, without asking too much what you were actually doing in more genral terms. I have always been trying to also provide explanations or point to existing background information with my helping posts. People who don't care about this should indeed better ignore my posts.

Bye Fridger

ar81 wrote:Don't take it personal, it is just how a newbie might see this place.

True. It is possible that a newbie MIGHT see this place that way. Certainly you have seen it that way - and you're a newbie - so, actually, I guess, there's the proof right there...

I, however, am also a newbie and my take on being pointed to a tutorial goes actually one step further than what steffens wrote...

steffens wrote:it is a perfectly acceptable help to point you to tutorials

...I would actually have said it isn't just "acceptable" it is gracious and helpful - especially considering, in most cases, the person asking the question often could have found the answer themselves by doing a search, rather than depending on others to do their work for them (with the VERY CRUCIAL POINT that it's not like anyone is paid to be here - they are taking the time to answer out of a desire to help which, whether their answers are helpful or not, doesn't change the fact they are TRYING).

Of course, to be fair, newbies such as us to bboards may not really be familiar with the concept that there is a huge wealth of information (and probably the answer to their questions) just a few clicks and keystrokes into a search function. Certainly I didn't know that the first time I posted on a bboard.

And when someone graciously took the time to tell me that the answer to my question had already been asked - and answered - half a dozen times and all I need do was look (along with giving me a link to a tutorial) - I was grateful for the pointer (and kinda embarrassed I didn't think to look for myself).

"How nice of them to help me out," I thought. "Especially considering they've probably been dealing with newbies like me asking the same thing over and over and over and OVER for years. Especially that Fridger guy with his five trillion posts... and that Selden dude with his five billion trillion posts. There is a lesson to be learned in their patience and giving. I am truly humbled. And thrilled to have fallen in with such a dedicated, knowledgeable, and helpful group."

But that's just me, I guess...

However, perhaps not. Perhaps it is another way of looking at it - an internal viewpoint shift - that might make this place seem a little warmer than it... well, than it seems.

Food for thought? Or am I making no sense whatsoever? I guess only time will tell...

Ar81,

naturally, I agree wholeheartedly with what Steffens and BlindedByTheLight wrote meanwhile in relation to your above "comments" about my helping style.

Bye Fridger

Fridger,
I hate to tell you this but your 2k cloudmap goes back farther than 2 1/2 years. Try over 3 years. It has been 3 years since I made the first version of HD 28185, I cracked the old zip open the other day and found your 2k cloudmap in there.

Now about the tutorials and such. I started trying to write a real good tutorial but I found that without adding a tone of graphics it was not working out well. Its just how I do things I guess. Now I took some time to figure out a better way. I ended up making a video tutorial that covers just the basics of cloudmap making. There is no sound except for mouse clicking. I am a little visitant to put my voice to the tutorial. Not that my voice is strange, its just when ever you do something like this you are never very happy with it or the way you sound. Of course you want it to sound and look somewhat professional. My biggest problem is video quality. I think if I can get a few of these video tutorials made it might be allot easier for everyone in general. We can simply point to the video. This tends to be a more visual medium so people are more likely to pick up the knowledge faster than reading. I can't tell you how many times I had to read over the posted instruction for making cloudmaps and the one for adding the specmap into the alpha channel before I finally got it right. If there is a video of the steps all they have to do is follow along. Well its and idea at least.

Don.

Don. Edwards wrote:Fridger,
I hate to tell you this but your 2k cloudmap goes back farther than 2 1/2 years. Try over 3 years. It has been 3 years since I made the first version of HD 28185, I cracked the old zip open the other day and found your 2k cloudmap in there.

Yeah, Don,

I realize we are all getting older /together/ around here
Time is passing simply too fast. But of course you are correct. I entered the Celestia community 3 1/4 years ago and did the 2k clouds not too much later...

Don.Edwards wrote:Now about the tutorials and such. I started trying to write a real good tutorial but I found that without adding a tone of graphics it was not working out well. Its just how I do things I guess. Now I took some time to figure out a better way. I ended up making a video tutorial that covers just the basics of cloudmap making. There is no sound except for mouse clicking. I am a little visitant to put my voice to the tutorial. Not that my voice is strange, its just when ever you do something like this you are never very happy with it or the way you sound. Of course you want it to sound and look somewhat professional. My biggest problem is video quality. I think if I can get a few of these video tutorials made it might be allot easier for everyone in general. We can simply point to the video. This tends to be a more visual medium so people are more likely to pick up the knowledge faster than reading. I can't tell you how many times I had to read over the posted instruction for making cloudmaps and the one for adding the specmap into the alpha channel before I finally got it right. If there is a video of the steps all they have to do is follow along. Well its and idea at least.

Don.

That is a gorgeous project! I hope you find enough time to realize it as planned.

I feel things have been going quite well with you lately?

Cheers,

Bye Fridger

My first Video Tutorial on making transparent cloudmaps is up in a new sticky thread in the textures section of the forum. It is in the Windows Video format and 16mb. But if you follow it closely you can't make a mistake.
You will need to download The GIMP to follow along though. I use the GIMP exclusively for making cloudmap transparencies.

Don.

I found a couple of interesting Photoshop Plug-Ins that may assist you. I don't know if they'd be any good for the more advanced Graphics Artists in the forum but, they may prove to be useful for someone.

http://www.mehdiplugins.com/english/eraserclassic.htm


http://www.mehdiplugins.com/english/erasergenuine.htm

The interesting thing about the second Plug-In is that it allows you to work with alpha channels by choosing which color you want to delete and which color to preserve. You must work with layers in order to achieve the desired effect. It just appears to be a potentially useful tool for those working on clouds.

t00fri wrote:The gimp is rather similar to PS, but FREE of charge and exists for Linux and Windows. Many of us like it very much (certainly I like GIMP a lot ;-) ).

And for OS X of course.
http://www.gimp.org.nyud.net:8090/macintosh/

I'm not quite an expert in Photoshop. I use another software which is not quite proficient in transparency.

Indeed I have never used it. What troubled me was how to turn a certain color to alpha channel, since using common eraser in a cloud texture is a bit annoying and not necessarily good.

Those plugins seem to be useful. Gonna try them...

Regarding the "get a tutorial reply", I understand that's some sort of help, but in a way it also isn't. My guess is that the role of this forum is not just to have a place to comment, but also a place to have a dynamic FAQ for other people with the same question.

The question of transparency as image processing may seem off topic, but it isn't. It is about making cloud maps for celestia. So it is a technical problem regarding creation of celestia add ons.

I tried DLing Gimp but some sort of problem arose and I couldn't install it. Gonna check out what's the problem. So my only option is photoshop at a friend's place.

I know no one gets paid to post and help, but also no one gets paid to make an addon which may result from those posts. So as I see it it is about learning, teamworking and then enjoying the add on.

ar81 wrote:
Regarding the "get a tutorial reply", I understand that's some sort of help, but in a way it also isn't. My guess is that the role of this forum is not just to have a place to comment, but also a place to have a dynamic FAQ for other people with the same question.

I think your arguments are very vague and far from convincing. Suppose, instead you were ready to study for several days, say, carefully page by page of one of the excellent /general/ tutorials on image manipulation techniques and concepts. Then you will for sure be sufficiently fit and perhaps have some leftover /specific/ questions. These of course could be answered in a much less time-intensive and concrete manner by the experts in the forum. That would be the effective approach to your cloud project.

I myself try desperately to push Celestia development ahead, which involved close to 100% of my spare time during the last 4 weeks. It was a big lot of research & development work to get e.g. the galaxy catalog ready with input data for more than 25000+ galaxies!

Now you come here with the reproach that I or other texture experts should spend our time teaching you these things that you seem unwilling to /first/ study by yourself. I for my part went through precisely these very time consuming efforts of step-by-step explaining already 3-4 times while I am a member in this forum, i.e. since ~ 3 1/2 years!

On the other hand, you you don't even seem to be willing to use this forum's powerful search engine for finding e.g. my previous posts and mini-tutorials on exactly the same issues.

Something can't be quite right here...

ar81 wrote:It is about making cloud maps for celestia. So it is a technical problem regarding creation of celestia add ons.

Many people in this community have made clouds before you! Your's can only become a valuable contribution for the users, if your clouds are coming out better and/or with novel features
This in turn requires that you intensively study the basics of image manipulation first...

ar81 wrote:
I tried DLing Gimp but some sort of problem arose and I couldn't install it.

This again sounds as if you are not trying very hard to get things done! Either your system is filthy (then I'd advise to repair it ASAP,) or you did not try hard enough to install. Please figure out for one minute how many people on this globe have installed the GIMP before you without any problems both in Windows XP ,in Linux and in Mac OS X!!

ar81 wrote:I know no one gets paid to post and help, but also no one gets paid to make an addon which may result from those posts.

If you scan through 'The Motherlode', you will immediately realize that there are almost too many addons! The problem with many of these is that either they don't run well or their graphics quality is VERY BAD. Same reasons again: their "creators" did not want to take the time for learning the required techniques first.

Nobody wants add ons that are mediocre or worse...

Bye Fridger

Hi ar81,

now look what you've done, you've made Fridger go all twitchy with nervous fatigue!

If I may try and help you... 'cos I'd like to share my methods and findings on cloudmap transparency with the forum anyway, to see if anyone's got better methods, even if Fridger did already mention several of my key stages in his first post there.

I find the best way to create good-looking cloudmaps is to use the cloud pattern as a grey-scale mask over a full white background. The default Celestia cloudmap for Earth originally came with both background and mask as the same cloud pattern. It can be improved just by flood filling the background with white.

By the way, the original Celestia earth cloudmap is a good example of a bad satellite image to use: It's a composition of geostationary weather satellite imagery, which can only cover up to 83?° of latitude. Unfortunately, it's been stretched over the poles and you see the radial spokes effect as a result. Use data from any low earth orbit satellite. Blue Marble data comes from the MODIS instruments of Terra and Aqua, that's LEO. Even so, if you are using the Blue Marble cloudmap, you'll find out later that there is still a seam at (I think?) 20?°S, 180?°E/W. This is a problem with the data Blue Marble used being incomplete.

Here's how I do it (in 'generic' terms, but of course I assume you use something as sophisticated as Photoshop, PaintShopPro or GIMP if you could get that to work):

1. Find/open or create a grey-scale cloudmap

2. Adjust brightness/contrast settings on this until the darkest parts are absolute back (RGB=0,0,0 - this will be 'no cloud') and the brightest clouds are absolute white (RGB=255,255,255 - this will be totally opaque cloud). There are three ways to do this:
i) Brightness/contrast.
ii) Gamma function.
iii) Histogram adjustment. This is best, if you have it. Look for a histogram tool (no, I don't know your experience level!). The histogram tool looks like a 'population count' graph. My tool has (at least) four widgets to pull: dark tone, mid-tone, mid-tone compress and highlight which start at grey levels 0, 128 and 255 respectively. The way this works is that if you pull the darktone widget above 0 to say 32, all pixels with grey levels below 32 will become absolute black, and the remaining pixel grey levels between this new dark tone and the mid tone are proportionately darkened. If the cloudmap was a satellite composite like from Blue Marble, there might be faint artefacts (usually quickly evaporating fog) that shows up as strips or seams. You can get rid of them using the histogram dark-tone adjustment. I adjust the dark tone until the 'fog' disappears. Similarly with the highlight widget, you can get entire areas of cloud to go bright white by pulling that down from 255 to say 240. Finally, the mid-tone will behave a little like the brightness function and brighten or darken the whole cloud map, while the mid-tone compress will enhance or reduce contrast by squashing or stretching the grey levels over a wider or narrower range of greys.

3. When you are happy with cloud apperance, create a new image that has exactly the same dimensions (and bit depth) as the current cloud map. Flood fill this new image with white (select RGB=255,255,255 and adjust tolerance to 100% if necessary to flood fill in one go).

4. Now the fun part. How you do it depends on what software you use: 'import' or 'paste' the cloud map into the new image as a "mask", or "transparency", or "alpha channel". Terminology varies somewhat. Search your software's help for these terms. You will have to establish yourself whether the software you use has this facility, by checking its help, or hunting about the menus. I hope you get the mask to line up!

5. Save the new image as PNG! JPEG and BMP won't save the alpha channel.

6. Try it out as your new cloudmap. Save both the original and adjusted greyscale maps somewhere, even though you can recover 'lost' cloudmaps out of the alpha channel of the PNG you saved.

I think you can extend this to colour cloudmaps: the mask should take the 'saturation value' of each pixel as mask opacity, and all the above histogram stuff still applies.

OK, if that's doesn't help you, then this whole topic is like someone asking where's reverse in this here manual drive hire car over a discussion board. G'luck.

Spiff.

Spaceman Spiff wrote:Hi ar81,

now look what you've done, you've made Fridger go all twitchy with nervous fatigue!
...

indeed


and if I may say so Spiff: it's quite obvious that YOU took some time meanwhile, to read about image manipulation basics ...

Bye Fridger

Hallo Fridger,

Nah... I generally never read the help files, unless I get stuck. I just try all the menus and buttons and see what effect they have first. How can you learn about an application if you don't try its buttons out!?



Spiff.