Planetary Ring using image maps

Started by Erwin0265, December 17, 2014, 06:59:40 am

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Erwin0265

OK,
I'm confused.
But then, I'm learning Terragen; of course I'm confused..............and frustrated.
Right - I'm trying to create a simple {err...cough..} planetary ring using image maps and a disc object.
I was working on a tutorial but when the instructor started to use multiple discs to create multiple rings, I thought... I'd better not say what I thought.
Now, I have numerous tgd/tgc files for procedural rings (some with rocks, some without) but I wanted to use image maps because, at this stage of my learning, I understand image maps (although I am still confused with mapping modes but I have that sorted in this case.............. even if I'm not quite sure why....).
Now, I started with using an Image map shader connected to the Default shader the disc already had (why the Image map shader can only connect to the colour FUNCTION input rather than the colour IMAGE input of the Default shader is beyond me, but there you go.........) but discovered the Default shader already has the ability to map images onto a surface so went with using the Default shader only.
I managed to get an image mapped to the disc (colour) but really started to have issues when I tried to create any sort of opacity variation (to create the multiple ring/variable density ring structures).
1. When opacity is set below 0.5, the disc is invisible! Why? Even if I set the opacity to 0.49, there's no disc (screencap 1) - however, it's shadow is still there........... This is whether an image map is mapped to the disc or not.
After a lot of stuffing around (a technical, scientific term - I have a B of App Sci - I know what I'm talking about... yeah sure...), I decided to try being a bit more methodical; even if my results didn't reflect the same...............
2. When I tried using a  simple big, black 'E' on a white background as a transparency map and started to get some results I understood (screencap 2).
3. Then, keeping the same map, I changed the opacity setting to 0.5 (screencap 3a) - the big E is still clearly working but notice the "spottiness" of the remaining disc..........
Then again, the same setting except for the opacity being dropped from 0.5 to 0.49 - only a miniscule change with a not so miniscule change (screencap 3b).
4. Up until now, the transparency map was a simple jpg; I thought I'd try a tif with a transparent background (so, only the big black E) (screencap 4a). Here, the transparency appears to have made the whole thing transparent..........
Then the same but with "Use alpha map" checked (screencap 4b). Now black appears now appears to be opaque, but that's because the alpha would be white; yes? So it's white that "keeps" the image opaque/visible?
5. OK; let's test this theory with a big white E with a clear background......... (screencap 5). So white "stops" the transparency function........I think.

All of this has me rather confused and I have yet to do the same with the ring colour map (Changing it to greyscale, inverting and then using it as a transparency map). This is because I need to understand the concepts I have highlighted in this post...

So the problems remain; why can't I get degrees of opacity/transparency? As it stands, white is opaque, black is transparent and greys having more black than white are transparent whilst greys with more white than black are opaque!
There appear to be no shades of grey........ literally.
Help!!

FYI; The last 2 images show the type of effect that I am after (regarding the rings); but these are out of Vue (which has considerably more issues than Terragen)...........
OK, who farted?

Erwin0265

I wanted to add this last image but it was too big to be part of the last post.................[attachimg=1]
OK, who farted?

j meyer

Please learn to use the search engine!
That has been asked and answered very,very often
before you even thought of joining the community.

Erwin0265

OK, some links would be kinda handy.
It took me around half an hour to create the post (screencaps, etc); that was after the 45 or so minutes I spent searching the forums for a solution to my problem/s.
WHY would I create a post like this if it's so easy to find the answers?!
You are undoubtedly more familiar than I with these forums; having ten-fold the number of posts that I do. Ever consider the possibility that what is easy for you to find, may be considerably more difficult for other, less familiar with these forums, to find?
I appreciate the fact that you took the time to respond to my question; I do not appreciate the fact that you intentionally provided zero useful info.................... >:(
OK, who farted?

Erwin0265

Anybody else?
I have spent the better part of last night going through more forum posts but simply cannot find what I need to know to continue.
Image mapping is so much more complex in TG (compared to Vue), but then, that's probably because there is so much more versatility in TG...........
OK, who farted?


Erwin0265

December 19, 2014, 12:02:37 am #6 Last Edit: December 19, 2014, 02:45:56 am by Erwin0265
Hi Kadri,
The thread you linked me to did have one of my questions (asked by EmDee 1) but no-one answered the question (bummer)...
Also, Mhaze made a request that concerns me:
QuoteAnd can we please have greyscale/partial/graduated transparency, please, please, please

-Does this mean that Terragen has no progressive transparency? It's either there or it's not? That is what I am getting in some cases............

The Effects tab of the Image map shader (as well as all of the other tabs) is something I have already read (at last 10+ times) - just not understood all that well..................

Seeing as I'm using TG3, I do have a bit of an advantage over the same issues in TG2 but I'll be damned if I can find what bits are new in the Effects tab.

Anyway, I think I need to attack this in steps; the first being able to keep a texture (err, I mean Image map shader) mapped to the surface of the disc (to be rings); currently, I can get the image to map perfectly on the disc when the disc is at 0,0,0 - but when I move it - forget it!
The disc can be translated AND rotated (using the axis parameter - what a pain the arse that is - why can't we just have rotate?); but the image map shader can only be translated. I imagine that the projection takes care of the rotation but I can't figure out how.
Using a camera to map an image is baffling to me - and there is little explanation in the wiki:-
QuoteThrough camera: The image will be projected using the camera specified in the Projection camera parameter.

Huh?
So, this is where I'm at.
Hopefully, you may be able to help me a bit more, or others may.
I guess, for a noobie, I am tackling difficult concepts but it's how I learn. I can only go through the basics so much before I want to actually create imagery........................
OK, who farted?

Kadri


If you use a UV mapped object for the image map you can easily move and rotate the object with it's image Erwin.


Erwin0265

QuoteIf you use a UV mapped object for the image map you can easily move and rotate the object with it's image Erwin.

Yeah, I know, but I'm not up to the stage of being able to create my own models; remember, all I am doing is trying to correctly texture a Terragen disc object.................
I'll check out the other thread; at a quick skim, it may have some info regarding transparency...............
I looks like Terragen's opacity is basically an "On/Off" set up; ie. no shades of grey/greyscale, so what I'm trying to do may not be possible........................... :o
OK, who farted?

Erwin0265

OK; I'm trying to use a plane rather than a disc to map a texture to.
My first issue is how do I map 1 to 1? I have increased the plane size from the default 1 by 1 metre to 10 by 10 metres but I can't find any setting within the default shader to do the same with the image so all I get is 100 little rings on a single 10 by 10 metre plane..............
[attachimg=1]
OK, who farted?

Oshyan

The Default Shader has a subset of Image Map Shader functionality, which primarily exists to handle imported models which almost always have UVs attached and thus options like tiling are not often necessary to adjust. If you need more flexibility, use an Image Map Shader, which includes tiling options, size adjustment, etc.

In regards to transparency, as others have indicated unfortunately Terragen only supports "binary" on/off transparency at this time. This is a rendering limitation and so is not easy to fix, I'm sorry to say.

- Oshyan

Erwin0265

December 21, 2014, 06:06:37 am #12 Last Edit: December 21, 2014, 06:09:57 am by Erwin0265
Thanks Oshyan, that helped a lot!
OK, now I'm playing with translucency with the goal of, perhaps, helping give the rings a bit more interest {due to the on/off limitation in opacity}.
With the settings I have tried, I'm trying to just see if I'm having any progress {ie. seeing if I have any translucency} by placing a spotlight underneath the plane/ring {so if there is some translucency, I should see light, albeit, scattered, coming through the solid parts of the ring}.
Unfortunately, I'm not even seeing the spotlight at all [ie, some point of light].
If I push the light to max [on the slider], the rings get totally washed out, so I know the light is working but I want to get a point of actual light; how do I do that?
I know, for example, in Vue, you will see the effect of the spotlight only but not the actual point of light - unless you check lens flares {and then go and uncheck all settings for lens flares as they are so overused to become almost as common as Photoshop's 3 lens flares.... BUT lens flares still needs to be checked ::)}.
I was wondering whether there was some equally weird way in TG to make a spotlight's actual point of light visible?
I hope I'm making some sort of sense here..........
I've attached the tgd file but obviously a few errors will pop up as the textures will be missing and they're way too big to post here............... But hopefully, someone can tell me what settings I need to address to get what I am after; both with translucency and the spotlight placement/settings.
OK, who farted?

Oshyan

Without an atmosphere, the spotlight doesn't have anything to create glow in, so it won't be visible. Other light sources, including Sunlight (infinite light source) have an option for "Visible Disc" that may do what you want.

- Oshyan

Erwin0265

OK, who farted?