Adventures in Radiosity

OK, so not really radiosity of course, but Ive been playing around with a technique for doing faux soft shadows, and hopefully diffuse lighting. Probably not the first one to think of this, but Im pretty happy with the initial tests so far so I thought I'd share some pics...comments are welcome.

Looks nice, but I'd make the prim edges transparent (or really flat with some prim butchering).

yeah thats the main giveaway, so Im definitely giving it some thought....the edges are actually 90% transparent (cant seem to make them %100??), but they still do the floating point flicker and also seem to pick up highlites on thier own...what kind of prim butchering do you mean? could I make a truly 2D plane somehow? I havent been able to figure that one out yet...probably simple, but I cant get the cube thickness less than .01

thanks!

It's easier just to use a completely transparent texture, but to butcher/torture that cube completely (well, 1mm anyway) flat, turn it into a sphere, set the begin and end dimpling to .49 and .51, then change it back to a cube and rotate/rescale accordingly (I believe it's the z axis that becomes horizontal).

/8/da/27520/1.html for more info.

thanks! I would never have guessed that...will give it a try tomorrow...

That is some sexy shadow-baking.

Good job

(Minor edits for edges notwithstanding - A+ for effort.)

Nice work.

Brilliant idea, excellent execution, Octal.

The edit window does indeed limit you to 90% transparency, but you can get all the way with this script. The script is gonna turn your entire prim entirely invisible, but then you can retexture the shadow side afterwards.

Thanks for all the encouragement and for the tips, as soon as 1.7 is online I'll be trying them out!

i like the build. I find it easier to toss a 100% alpha texture onto all sides of the prim, and then place the shadow texture just on one surface.

if you want to save prims, bake (i.e. draw) the shadows directly onto the texture.

Of course this means you usually have to repeat (tile) your texture 1x1 on your prim surface, so you have to get build any repeated tiling into your image. You lose some sharpness if you stick with a 256x256 px texture (spread 1x1 over a large prim, it will lose focus), but you get the return of being able to edit away some of the obvious repeat effects (for example: in a brick wall, that patch of orange bricks showing up in the exact same way every 2 feet) which hurt the realism of a build...

while shadows force you to fix a light source and intensity, i still prefer builds with them to without... without shadows everything looks so flat!

Just a few comments.

The darkening towards the corners of the room seem a bit too abrupt, so they appear more like dirt in the corner. Try using a more gradual drop off and it should look nicer.

Also, for anyone who wants to experiment with radiosity just to get to know it better but don't have access to any software can try DIALux. Its a free software used for lighting analysis and is fairly simple to use but produces nice quick results. Don't forget to download some light fixtures as well from the various manufacturers.

http://www.dial.de/

YAY!! Kick ass man! Thats really nice. Keep at it! I look forward to seeing some more of your stuff!


I've done a few builds in the past using full radiosity baked out of Lightwave and the results were pretty good, but its very very time consuming. Quite the pain in the ass really.

Nephilaine does a ton of painting shadows and ligthting in to her builds, take a look at the PD or TorridWare buildings in Chartreuse. Chip midnight also did a few neat builds with full radiosity baked out of 3ds max. His cornell box was really really cool. Jimmy Thompson has done some pretty cool stuff in this regard as well, I highly recommend taking a look at his builds, really good ideas in there. To those in that paragraph I mentioned (and anyone else who has done this, post some pics of examples please?)

I have found the most economical way to get these into sl is either creating an alpha shadow overlay as you have done, or to paint the shadows directly on the map, this is my perferred method if I am adding lighting in addition to shadow, but if its just a shadow I will use an alpha on a prim, its amazing what you can get away with using that!

I have a few builds up right now that show baked lighting, lighting painted in photoshop and also alpha shadows on a prim. You can find the first two at the whitestar skyboxes, the egyptian room is baked and the tyrell office is painted. The whitestar institute was done using alpha shadows.

The method I usually use for making shadows of objects is to do a top down (or side if I want elongated shadows) of the object on a white full brite prim and then ship that over to photoshop. Then I go through and make the sl object black and seperate it from the bg layer. Then I run the equivalent of a box filter (motion blur at 90degrees on one layer, and 0 on the other) and then run a gausian on the result. I usually make the alpha for it near white (aside from the fall off) and then use prim alpha to change the transparency.

The photoshop lighting tool can actually be used to a decent effect if you tweak it enough, using one of the channels for bump (lower corner of the lighting tool) works decently in adding a bit more depth than just the standard lighting filter. Hope something in here was useful.

Anyway, here are some screens....


WS Casino 2
WS Casino 3

Egyptian Room 1
Egyptian Room 2
Egyptian Room 3

wow neil, nice stuff! where is that Egyptian room? I searched but could not find...:/ Would love to visit there...

Great shadow work, really well done, and yes a pain for sure. Seems like everything is gouraud shaded in SL, no phong-like hilites or anything, so its extra work to get any sense of depth or realism but worth it IMHO.

I'll check out some of your other references too, thanks!

You can find it at.....

secondlife://Chartreuse/20/75/

I did a LOT of shadows (alpha only) in Active Worlds for Hole world over the years. http://tnlc.com/eep/aw/sites.html for pics (and check out the screenshots for more). I haven't messed with shadows too much in SL yet but it would be interesting to try and adjust positions relative to the sun. I've tried a sundial shadow like that but it needs more work to adjust the prim shape as it moves around the circle so it doesn't stick out over the edge.

All I can say is WOW!!! You are the person I'm looking for!!! Your examples seem the most photorealistic of any I've seen before!!!

I am just a complete beginner in the 3D modeling field, In fact, I was never interested in it up until I discovered what one can do in SL.

I was just wondering though. I was able to keep up with your post but I couldn't understand everything since I don't don't know how to use photoshop or lightwave.

But I will purchase those two applications just for the purpose of creating my home hehe

Would it be possible to explain to me how one can go about exporting an object to lightwave or photoshop, do that texture backing thingy, and then putting it back into the game?

Also, how do I create shadows for objects, within in the buildling as well. If anyone could help me with this that would be great!

I would like to build a house with correct global illumination/radiosity whatever it's called, so that I can have the most realistic looking environments possible. If anyone can help me I will compensate them for their time to list the steps. Thankyou

Sincerely

Sarah Enigma

I made one of those a while back, you can check out one on display at the Weather Achives in Neualtenburg.

Shouldn't be too hard. I would use a cylinder prim for the gnomon. That way you can rotate the edge of the (rectangular?) shadow prim through center of the gnomon prim and not run into any weird clipping artifacts (hopefully). Although as you adjust the length of the shadow prim for the time of day, the shadow prim is going to want to move away or through the gnomon prim. So, you might need the script to adjust the angle, adjust the length of the shadow prim and then move it to keep it just in contact with the gnomon prim. Or you could have a shadow prim that is centered on the gnomon and half of it is transparent. That way you don't have to move it as you adjust the size. However, that might bring up the weird trying-to-see-one-texture-through-a-transparent-texture artifact.

Or you could just fake it and have a sundial surface with so many textures with shadows baked for different times of the day and just load each acording to the time.

Since the grid is down and I am up, this is as good a place as any to explain how I do this stuff. Feel free to chime in with questions.

First lets talk about what you need to do this. I will explain using Lightwave, I choose Lightwave because its the simplest and fastest way I know of. I have used Maya for baking before, its a gazillion times more difficult in almost every aspect, so I recommend LW for this task. I have seen good results from 3dsMAX but I am not a 3dsMax user so I will leave that explanation to Chip or someone else.

Photoshop is not necessar though has some nice features. Gimp is 99% as good and 100% cheaper. Get gimp, it'll save you $600.
As for the other software you need.......

Lightwave 3d - $795.00 (my my they have gotten cheap)
http://www.newtek.com/
Microwave baking plugin for LW - $499.00
http://www.evasion3d.com/
Photoshop CS2 if you must.... - $599.00
http://www.adobe.com
GIMP - FREE!
http://www.gimp.org

First I will explain the basics of the setup, to give everyone an idea of what one must go through to get accurate lighting. Its not a difficult task by any means, but its very very tedious. No doubt parts of this will become easier as SL matures.

Basic overview of process for baking for use in SL.

1) Create the build you wish to bake in SL.
2) Re-Create the build in Lightwave Modeler
3) Create uv maps for each face you wish to bake.
4) Create surfaces (these are different than the uvs)
5) Export the model to Lightwave Layout.
6) Light the scene. This is by far the most critical part.
7) Tweak tweak tweak tweak tweak.
Bake textures using microwave.
9) Cleanup maps in PS/Gimp
10) Compile texture sheets.
11) Import into SL.
12) Apply texture sheets to build.

I will skip part 1, assuming if you are trying to do this you will already know how to create something in sl. For this psuedo tutorial we will be making something simple. Create in SL three boxes. One is going to be 10m x 0m x 10m (ground plane), the next will be 1m x 1m x 1m resting on the ground, and another that is 1.5m x 1m x 1.5m this one sits directly on top of the last one. This setup will allow us to generate some basic GI shadows (the overhang) and some normal shadows.

Now comes the fun part of bringing that on over to LW. Open Lightwave Modeler and create boxes the same dimensions and posisitons as those in SL. To my knowledge there is no automated way to do this, you just have to write the numbers down and enter them in manually.

Now once you have that all created now comes the ubertedious task of creating your uv's. Select the top face of the ground plane and create a new planar Y mapped UV, name it something memorable, I choose GroundPlaneTop. Now select the +X axis face on the next prim up, create a UV map with planar X mapping and name it something like Prim1_+X, now go through and do that with the other 3 visible faces. You should end up with Prim1_+X, Prim1_-X, Prim1_+Z, Prim1_-Z. One thing I should note now, Lightwave is set up for Z being depth and Y being verticle. Now, do the same thing for the top box, only this time you will end up with 6 faces mapped. So far we are up to 11 images we are going to bake......for 3 boxes...one begins to see where the tedium comes in to all of this. Now one could make this simpler by making each box have one atlas (non connected projection uv) uv map, but then you need to try and remember which face is which in the map. I figure, we can save that step for now. Save the object.
Now select the top face on the ground prim and create a new surface called ground or something like that. Create as many surfaces as you like for each object, it will vary completely depending on how you prefer to surface. For those who are just starting to do this kind of thing and only have SL experience to this point, I recommend one surface per face, this will allow you to surface similar to how you are used to surfacing things in sl. Once you have created your surfaces for the three boxes save the object again.
Open up lightwave layout, import your object. Layout is where you will do all the lighting, surfacing and rendering for your scene. Once you have your object imported save your scene. For this specific psuedo tutorial I will skip the surfacing part as that isnt really what we are talking about and isnt necessary for illustration.

Now its time to setup your lighting. This will require going back in to modeler to create the GI dome. But first I want to talk a bit about how GI/Radiosity works.

Radiosity
<graphics> A method for rendering a view of a
three-dimensional scene that provides realistic lighting
effects, such as interobject reflections and color bleeding.
Radiosity methods are computationally intense, due to the use
of linear systems of equations and the spatial complexity of
large scenes.

Ok to sum up what that says, radiosity calculated light bounce. In a traditional 3d scene there is no light other than what you create, if you have one light lighting up one side of the object, the other side will be 100% dark. With radiosity (depending on your setup) the otherside will have light, but it needs something to come from. You could create a 360 degree lighting rig that lights evenly from all sides but this is a ginourmous pain in the ass, so lets save ourselves some time. Radiosity can cast light from objects so creating a 360 degree lighting rig is as simple as creating a sphere. So lets do that. In modeler create a sphere, now cut the the bottom off of that sphere so we are left with a 180degree dome above the objects, invert the faces of the object so that its an inward facing dome. Change the surface on this to GI DOME or something like that. Save the object and import it into your Layout scene.

Now lets check a few rendering flags for the dome. Open the rendering properties for the dome and make sure cast shadows, recieve shadows and self shadow are unchecked for the dome. You can also check unseen by camera if you like. Now we need to make it cast light. Open the surfacing panel and select your GI Dome surface and set the luminosity setting to 100% and the diffuse to 0% (its going to cast light but recieve none).

Now open the global illumination panel and enable radiosity, for time purposes we are going to use Interpolated radiosity vs Monte Carlo, Monte Carlo is far more accurate but of course that means longer rendering times.

Ok thats all we need to do to setup our lighting rig. Now this is going to be very very basic lighting and quite uninteresting, but thats fine for now. Lighting is an art and take a long time to really master, I highly recommend taking a lighting class or reading a lot of books on cinematic lighting. Anyway, hit f9 to render the scene and you should now see your objects being lit and all that jazz. Now of course there are no shadows and it rendered in like a fraction of a second....whats up?? Lightwave assumes that you want it fast and ugly, so its default setup is for that. Open the rendering options panel and select enable shadows. Now we also need to move our camera to a view that can actually see whats going on, so select your camera and move it to where you have 3/4 isometric view of your object. Now render. This should take a couple of seconds as this is a very simple scene. But the result should be fairly nice....should look something like this.....



Not bad, not great, good enough for our purposes. Now comes the baking part and you guessed it, more tedium. Assuming Microwave is already installed and loaded into Lightwave open the Image Processing panel. Then under the pixel filters select Microwave, in Microwave you will select the object as the project object, and then select on of the uvs for it. Select the items you wish to bake (just set it to Render for now) and then set the image output. Do this step for EVERY uv you created.

Now hit f9......and mow the lawn, get some coffee, fly to japan, spend a week there and then come back, oop not done yet, well clean your house or something. Ok now its done. You have 11 images with shading and the whole nine yards. Fantastic.

There may be rendering errors, some of them may just look like nice detail you didnt have to paint, but some of them may be ugly as sin, so if thats the case this is a good time to fire open photoshop and clean them up. I wont walk you through that step, its just a matter of clone stamping and blurring etc. In this step I like to make texture sheets. This makes it so you only have to load in a few images vs all 11. This also means that you cannot apply it direct to a face in sl and have it work, you have to use scale and offset to get each cel in the right place. I can explain this process further and why I do it, why its worth the extra tedium etc, but the summation is SL will love you for this. It has only 3 images to download vs 11, which is good for the people who come there, though the only thing they will notice is how fast it loads. Expect no congratulation for this process, but do it anyway, its just good game development form.

Thats about all there is to it. On a large build this is a SERIOUS undertaking. The pics I posted were the cumulation of well over 3 months of part time work. This is not a process for those who just want it done. However that does not mean that those who just want it done now have to suffer without shadows. I will be posting again shortly with some explanations of how to create shading using just photoshop. However that will be later today as my hands are tired of typing.

I hope this gives some of you the inspiration to do this, I really do. SL could look like all of those other games if everyone did this. The only reason SL doesnt look like other games is because people dont do this. So for those of you who complain about SL look so far behind the times, get busy folks, you are in control of that as much as the Lindens are, if not more so. Now they could make it a lot easier on us, but we will wait for that.

Cheers and happy shadowing!

and for those that have used Photoshop before but cant afford it at home:

GIMPShop
makes the Gimp more recognizable.

Haven't really used it all that much yet myself but it's definitely worth a try.

L8r,
UU

just a post of encouragement Neil -- THANKS for the explanation above and I can't wait for your next post.

for some current projects, I've been baking in shadows in just photoshop (haven't been willing to shell out for yet another expensive sw program) using a mix of photographs from SL and drawn light/shadow elements on different layers with different layer types and some rendering light on top of that

i haven't locked down a particular method yet so no formal process to post at this point.... and I'll probably learn a ton and improve something based on Neil's next post

you can go really nuts with shadows in SL if you try to catch the light play on every surface and angle... what i find an interesting challenge is finding that balance... just enough shadow that a build feels more immersive, but not so much that your texture lag or prim count is insane (or that your head explodes before the build is done)

Cheaper way. Take a some (good) art classes dealing with light and shadows. Of course as your subject becomes more compex, the more attractive those tools become.

True, true, true. There are a few problems dealing with shadows in SL. One is that we (usually) have no control over the source of light in SL unlike other games. Which means applying shadows in rooms with a lot of exposure to outside light can sometimes look odd. Better than without, but it still bothers my sense of aesthetics. I am thinking shadows-lite might be a better approach. Enough shadows to take the harsh edge off buildings and to give things depth, but not enough so you spend all day hunched over the computer rendering. Oh, and I would love to be able to cast shadows onto the ground. I have this house on posts about 1m off the ground... If I put a large enough cube underneath, made it dark grey or black, and then transparent...

The second is that it increases the burden on the PSer or GIMPer exponentially. Tiling textures is often out of the question. You can't have a wall with shadows meeting in the middle unless you are using wall sconces for lighting. So... textures have to made in specifically for each prim. But I might just be a stickler for shadows curving correctly in the right way on every wall. I just wonder if someone dropped some houses with baked shadows into the market at zero cost (through GNU for example) would this serve as an impetus to other builders to ramp up their efforts to stay competitve.

Don't get me wrong. Builds with baked shadows and highlights for effects that don't move and transparent prims with shadows and highlights for effects that do move are in the works... Ever so slowly though. I just wonder if all the good image designers flock to clothesmaking for better returns for their efforts. That and you have good spatial sense and well as artistic talent to make this work.

I Humble Myself Unto Your Greatness. Lord Neil Protangonist!!!!

May The Gods Of Athra Bless You With All The Bounties This Universe And Beyond Has To Offer!!!!

I Will Make A Pilgrimmage To My Computer And Go Into A Developmental Fasting Until That Time When Our Divine Temple Of The Celestial Has Manifested Itself Into Full Flourishion!!!!!

It Is People Such As Neil Protagonist Who Make The World In Sl And The World In This Dimension A True Work Of Art!!!!!!

I Share Your Vision Of Artisitic Depth Neil Protagonist, But I've Yet To Find Anyone, Including Myself, To Have The Ability To Make That A Reality. Until, You Came Along!!!!! I Will Forever Praise The Gods Of Athra That You Will Have A Long Fulfilling Life And That All The Powers Of The World Throw Themselves Under Your Guidance For Beauty In This World And In The Real World. If Only Others Would Have Such A Prolific Mind And Vision, Which You So Naturally Possess!!!!

Geez Neil, youre good and all, but I think I just threw up in my mouth a little..