Forces of Light and the Geometry of Shadows

[Shadow Assassin 336]

Now, this is one to bookmark!

Thanks to you, I am definitely going to go back to 3dsmax modeling... I currently use gMax *boos from audience*, only because 3dsmax refuses to render my stuff for SC4... must be a BAT issue.

If only I could fix it.

[SimFox 804]

Welcome aboard Shadow_Assasin! I’m sure may here, me included, will be glad to pick your brain and experience. What sort of problems do you have with Bat4Max?

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So let’s conclude with COLOR thing I’ve started on previous page. If you remember, those tests were to illustrate concepts of SATURATION and BRIGHTNESS. And they show that our eyes play tricks with us now and then. But there are few ways to represent colors in a very exact fashion, with numbers. These are normally intended for the machines. Humans tend to rely on their subjective perception, which is fine if that perception is trained, or if it is used just for own consumption. There like /don’t like is all it takes. But problem arises when those opines become traded, shared, when people start telling to others - oh, that’s to bright , make it less bright or somethin’. What do they mean too bright and how do they expect “not so bright” to be?? This problem is not exclusive to simtropolis. It is common occurrence in interior design, graphic design and any other form of human activity dealing with color. So sometimes numerical values could be of great help to humans as well. Plus understanding them could also train the eye and own subjective opinion making process.   There few ways to represent color in numbers. Two most common are RGB and HSV/HSB. First one RGB is a set value of intensity of each of the primary colors measured from 0 to 255. RGB of 0,0,0 is absolute black and RGB of 255,255,255 is pure white. Whenever you have all tree numbers same you have neutral grey of various degree of BRIGHTNESS.     RGB system is better when you’re trying to change a hue. But when dealing with brightness then I prefer HSB/HSV. HSB is used in Photoshop and measures H (hue) in degrees (on color wheel 0-360) and S (saturation) in % same for B (brightness). HSV used in MAX assigns values of 0-255 to H (hue) S (saturation) and V (value – same as brightness in Photoshop). Here are screenshots from Photoshop and Max showing those respective color selectors.

General rule of thumb is to avoid values above of 230 for either brightness or saturation, as such a color doesn’t behave naturally with about any lighting situation, and most rendering systems will be having very hard time to deliver result with any degree of naturalism.

Notice that any difference of shade is gone into one radioactive like glow.   Reducing both Saturation and Value to 230 still leaves us with bright, well saturated RED in normal lighting situation and preserves clear separation of surfaces according to the amount of light received when light is increased 10 fold!

This isn't some sort of trick. There is solid physics underling this principal. Object with full saturation (255 in MAX's scale) reflects ALL of light of this particular shade. This isn’t very likely situation in real life, as no thing as 100% reflection of any kind really exists. And brightness of 255 is even less possible!! That would mean that ALL light received will be reflected - object would be PERFECT mirror, something that doesn't exist! Our subconscious is very much aware of this physical principle, although out mind doesn’t necessarily fully understand science behind it. So that's why when we see object like this we perceive it as GLOWING - meaning GENERATING light!

 

[SimFox 804]

Let there be light! This is long overdue revival and expansion of my short note on different possibilities for LIGTHITNG and RENDERING stuff for SIMCITY. Lets start with the LIGHT. We see world surrounding us as a light cast by various light sources – natural like our very own star – SUN, or artificial – all sorts of lamps and bounced/reflected from object around us. So, naturally in the world of 3 D modeling same approach is followed to recreate the world. Given that all 3D is nothing more then imitation/simulation of the reality done through various tricks same is true to the light in 3D.   If you look at any outdoor day scene, where does the light comes from? From Sun? Right, Sun, as naturally light emitting object, is producing something referred in 3D as a Direct Light. But not all light you see is such a direct light. If that would be the case then in the areas shaded from the sun there will be complete darkness. In reality that is not the case! This is due to the omnipresence of indirect light – one produced, or to be precise scattered by Atmosphere (sky) and all the objects around us. You’ll probably also notice that this light has distinctly different properties then Direct Light, but these are beyond the scope of this article. This lighting environment is recreated in BAT via something called Lighting Rig. This is simple collection of various lighting sources this different properties. Lets’ take a look at the default lighting rig that comes with BAT (either version of it). But this one is from GMAX BAT:   Front view   Top view We can clearly see two sets of light. The group on the left represents SUN. Lights in it have warm hues simulating the tones of the sun light in later afternoon. Lights grouped on the right provide “indirect” light of the sky. And naturally has bluish hues. SUN 1 SUN 2 SKY /SHADE 1 SKY / SHADE 2 In my personal opinion those have been selected not in a very best way, since they DO NOT quite match lighting scheme of the game engine itself. Coloring is not the only mismatch. There is even bigger and absolutely incomprehensible screw up – direction of the light in lighting rig doesn’t match one in game. But for now we’re going along the lines of the rig. Complexity of the it’s design is a heritage of times long gone when computers were slow and 3D software very green and is due to  if I may add, very poor quality result is due to the antiquity of its design dating years back. Another major problem with this rig is quality of shadows it generates. Lights in rig set to use ShadowMaps for that purpose. Result is shapeless blobs which have little in common with the objects that suppose to generate the shadow. This is a major reason behing simplistic box shape of most Maxis buildings and hard time battes have when they try something triangular etc. But as time is going on, huge progress in computing power made much more realistic representation of the world around us possible . Also adaptation of BAT to work with 3ds Max – one of the most powerful off-the-shelf 3d package made the original lighting solution completely obsolete. So let’s try to create entirely new system that will utilize both software capabilities and raw computing power of present day CPUs. To begin with let’s clearly state our goal. What do we need? We need a system that would approximate natural outdoor lighting on a sunny /partially overcast day. To get there we need both direct light – Sun in our little fantasy, and indirect light of the sky. Most straight forward solution would be getting one Direct Light to be our sun and then Sky Light to be our sky. This is perfectly valid configuration, but it could still be improved upon to get setup even more simple and universal. Using Direct Light as our sun we are faced with one technical issue – falloff region of the light. We have to set it manually as default setting could be not big enough for some structures. Also elevation could be an issue for taller structures. Of course nothing preventing you from putting the sun several kilometers up but still there is a better, simpler and more elegant way to resolve this issue! Max at least starting from version 6 comes with something called IES Sun – you can find it in Photometric subsections of lights. It is basically same direct light but independent of Falloff and height limitations of regular Direct light. At the same place you’ll find also IES Sky.   you'll find both IES Sun  and Sky in Photometric subsection of lighs section of Create menu Ok let’s start building our new Lighting Rig! First let’s create SUN. Just put IES Sun or Direct light at the place where main light of default rig was located. I would very much recommend you to go thorough all of the lights of the default rig as to get better idea what they were representing. This may help you to create some custom rigs that would be better equipped to deal with some particular situations you may face later. But for those not inclined to do so here is a set of valid coordinates. XYZ -474; -352; 575 Done that place the sky light into the scene. Again you have choice of either default Max’s Skylight or Photometric one. I would suggest to go with photometric one as it offers some extra settings. You can place it anywhere in a scene as long as it faces directly down.     This is what your ready Rig should look like Having placed our light sources into the scene let take a look at their Intensity, Shadows and Color.   Default values for both IES SUN and IES SKY are very high and meant to be used with so called Logarithmic exposure set to exterior day scene. This is one way to equalize bright and shadow spots and deliver believable daylight system, but there are couple of problems with it. First one is by doing so you would have to accordingly increase the strength of all your NiteLites if you’ll fail to do so you very well may simply not notice them after rendering. And second is that you most probably will not have access to those controls as installation of BAT4MAX highjacks PlugCFG line in 3dsmax.ini. There are ways around it but for now let just reduce intensity of our light sources. There aren’t any ultimate values and I would encourage you to play with them to develop the sense of it, but here are some which you may use as a guidance – IES Sun 800-1000lx and IES Sky 0,04-0,05. Also I would recommend to set IES Sky to Partly Clouded, but do try other settings and see which one you find more appealing to you.  To be continued...

[moganite 4]

.... loks like i will have to switch to 3dsmax now to find it.

As i am starting to increase my complexity of my models I think i had better go up to the better package.

[Jasoncw 12,060]

Cool, I look foward to the next section.

[paulvmontfort 617]

thanks, I'll be able to better light my scenes.

[SimFox 804]

I would like to dedicate this little tutorial to BIXEL – our beloved bat machine. For some time he was wondering about texturing “curved” objects like stretch of a road, or something along that path.  So let’s make a road! The best way in MAX (I know of) to create such an object is LOFT. Loft, along with Boolean etc., belongs to the group of so called COMPOUND OBJECTS – those made of more then one “ingredients”. In case of LOFT those are Path and Shape which will be extruded along it. Most wonderful thing about Loft is the fact that not only it creates geometry, but also maps it in a way that would be humanly impossible (or very lengthy and complex) to do otherwise. I hope people reading this are familiar with abbreviation UVW – texture map coordinates space. What loft does – it maps U along the spline or other path you’ve chosen and V across it. Ok let’s make us some Lofts. Here are two ingredients – simple enough. I normally start with SHAPE, but there isn’t really any reason for that . you can do you path first as well. OK here is our SHAPE:     It represents cross-section of our future Loft-road. I guess there isn’t any need to explain how it was made – sufficient to say that it is editable spline. This done, to the task of creating Path:    This is even simpler – just line with filleted corners.   I want to say couple of words here about the Curve. Curve is a mathematical concept. Unlike Vector Graphic packages Max represent it graphically through the finite number of straight sections. So the closer you get to it the more apparent it becomes that you’re faking it, baby! This number can be selected prior to line/Circle, etc creation in Interpolation Roll-Out, or altered afterwards in Modify panel to suit your requirements. Default value is 6. One way to ALWAYS have smooth curve is to check the Adaptive option – that way the closer you get the more steps MAX will, on a fly; stick in – eternal bliss! But beware as it could make geometry “heavy” and doesn’t work Post Factum – for instance Loft based on such a path will not update with zooming in. But no worry, smoothness of your Loft can and should be modified internally. I’ll return to this topic later.   OK all we need is here lets LOFT.  To do so select your path and then chose Loft in Compound Objects of Create Panel: This will bring you to this menu:     There are few items here I would like to you pay some attention. Take a look at Creation Roll-Out. There are tree option as to the destiny of the ingredients of the Loft – Path and Shape. First – Move – both get consumed by the Loft creating and are no more. Second – Copy – both Shape and Path are preserved but not connection between them and future Loft. You can edit them and it will not affect Loft in any way. And third – Instance – as name suggests both are instances in Loft – giving you possibility to edit either of them and see Loft changing instantly before your eye! It’s pure Magic! I guess there is no need to explain which method I would suggest to use! Ok, taken decision on the creation method choose get shape and select the Shape. Your cursor will change like this when you are over “allowed” object:     Done that, this is what you may see:     Doesn’t look very smooth, does it? Let’s fix it from within the loft. Select it if for some reason it got itself deselected and open Modify panel.  There open Skin Parameters Roll-Out. Here is what you should see:   I guess there is no need explaining Capping thing, so let’s take a closer look at Option Group. Here you see Shape Steps and Path Steps. Both are crucial to the appearance of your Loft. Path Steps controls number of steps along the path and Shape Steps across it.  Remember how angular did our road look with just 5 Path Steps :     here is what it looks like with 22 Path Steps:   Ok, now let’s tackle the Mapping! Create simple Checker material – ideal tool to check (pan intended) Mapping issues. To do so place Checker Map into Diffuse slot of the Material.    Apply it to the Loft. Remember to make it visible in the Viewport!   Here is what you might get:   Your actual look may differ depending on exactly where you model crosses it’s way with this procedural map. Any way, this doesn’t really matter as I’ll explain now what you should do to get it look right. In Modify Panel view of Loft open Surface Parameters. There are tons of interesting and important stuff there but for now we’ll concentrate on Mapping Group. Here is what you’ll (most probably unless you were tampering with it already) see.   Apply Mapping should be checked as this is, actually, what tells Max to do it wonders. I’ll not go into Real-World Mapping – check MAX’s manual for that, but let’s take a look at Length Repeat and Width Repeat dialers. These control how many times Mapped UVW space will repeat itself along the length (U) and along the Width (V) of Loft. Here does magic start! Go and change those values! This is what it looks like with values as seen in the screen shot.   There is one more issue here though… Take a look at this render of the loft with Length Repeat of 200 and width Repeat of 4,4 At first it may look fine. But look carefully – checker ignores the topology of the “central bump” it stretches across it as if there would be entirely flat surface despite the fact that light indicates otherwise.   To resolve this issue we should go back to Skin Parameters. I had 0 Shape Steps at the moment of that render. For something flat or only with clean linear corners it would be fine, but bump on our road is a curve. For UVW mapping to be able to cover it properly it needs some steps there. Increasing shape Steps to 5 solves problem: Hope this will help everyone to avoid all so many mapping and texturing blunders and open new horizons in your creativity!

[bixel 1,228]

I am humbled.

[SimFox 804]

that's good, but did it help you?

:-)

[bixel 1,228]

It will. I am too busy right now to do anything yet. But expect the revival of my highway peices next week.

[edit] AWESOME!! This worked out really well. I had to use it in my recent project. Thanks.

[Jasoncw 12,060]

Thanks!  I might be lofting soon so this will be helpful.

[mightygoose 92]

awesome tutorial , i assume this is also a quick way of doing lots of pipes...

[Jasoncw 12,060]

Pipes can be made by checking the boxes that make the splines renderable.  In the omnibus there's a tutorial called "lesson on lattice" or something like that, and it's the same thing for 3ds max.

[paulvmontfort 617]

I've been working on a house lately, and i was wondering how i can get the inside a bit brighter:

I tried changing the number of bounces in FG and I tried adjusting photon emission but they didn't work.

[SimFox 804]

Paul, you can play with Brightness and Mid Tones on the Environment Tab in Logarithmic Exposure Control Parameters.

But those will have universal effect.

if you want to stricktly limit the effect to the interior of the house then you would have to light it up.

[SimFox 804]

This tutorial will be in two parts – short one, that simply explains how to set up night library and then load it assumes you know what self-illuminating materials are and able to set them up. Long version will explain a bit about self-illumination as well and will be available sometimes later. So here we come, PART I (the shortcut) Setting up new library. open new scene. This is important!! This has to be ENTIRELLY new scene, not simply reset one as max keeps all the loaded scripts since the instance of the program has been open and all the info about stuff like your libraries , SC4Model filename etc is stored in BAT scripts and will remain there even if you reset your scene. So OPEN NEW INSTANCE of max. in the empty scene open material editor and select Get Material from its Material menu. New window titled Material/Map browser will open. In Browse From frame select Mtl Library and then press Save As in File Frame. Give your library name structures as follows: *_night and click on save.   Now you have yourself an empty material library that could be loaded and used during night render pass. This done now you’ll need to populate it with materials. Only those that would be different then the day ones need to be stored in it. Now you have tow options how to fill it with materials:    If both, your scene and the materials you gonna make are relatively simple and you have memory good enough to keep track on all stuff in your BAT you can create all the needed material right there and then in the same empty scene where you’ve just created your library. After you’ve saved it the Material/Map browser window should have stayed open. It is empty now indicating that there is nothing stored in the library at the moment. Create needed materials and simply drag and drop them into this empty field. It is that simple once done click on save and all will be stored in your library. If your scene is complex, you material would need to be adjusted to sit right on the UVW maps you’ll be better of opening your scene saving it as a copy and then open in it the empty night library you’ve just created. (Mat Editor ->Get Material->Open) create/edit all the materials you need, once done drag them (only those that would be different during night render) into the night library and save.   To use Night Library you would have to load it prior to export. This is exceedingly simple: open Mat Editor Select Get Material Choose Open in File frame of Material/Map Browser window Select proper Library from the list and click open. Once done you’ll see that text right under Render BAT button in Export Roll-out will change and read something like this: Current Material Libraries (followed by the name of your night library) and statement “Night Library will be used”.   Now, just click export and you're set! PS on naming convention… Read me file that comes with BAT instructs to name those night materials in a particular way - with windows, doo etc prefixes. In my practical experience I’ve found this to be irrelevant. All what is needed is that day and night material used for same object would have identical names! And to make it very clear - there must be a PAIR!! You can not use only night material. There MUST be the DAY version as well!

[fabfab 4]

Great! That's what I needed - thank you so much, mate!

I'll use a NightLib right on the next project... OMG, this will save me lots of time adjusting lights for faking Night-Windows. And they will even look better - HOORAY!

[Jasoncw 12,060]

!!!

I didn't notice you posted this! I'll try it out later on, one of my buildings will be relying on this for niteliting. Thanks for posting.

[SimFox 804]

Let me know how it will go...

[ianpaschal 77]

I think simfox, if you aren't interested in discussing it, then I will, but some weight should certainly be given to Near and Far Attenuation ajustments

[AndisArt 2,068]

This is amazing stuff here, thank you for sharing!

What happened to the pics on the first page? Some are missing on this page as well. Any chance of getting them back?

[SimFox 804]

Sorry, I don’t know why those missing pictures are just that – missing… All of them are stored in imageshack and unfortunately I don’t have duplicates of them anymore – were deleted when I was moving stuff to new machine…

Sometimes reloading page helps to retrieve pictures which weren’t loaded for the first time…

BTW when I choose edit message I can see those “missing” pictures which wouldn’t show when page is displayed normally in IE7, they however show fine in Firefox (those PNG ones)

PS
Some images (those PNG ones) were not properly displayed in IE7 cause it for some reason couldn't determine their size and was showing them as 0x0 pixels. I went and manually set proper size and now they should work.
Missing pictures on the second page (in post dealing with Lighting rig) are just that - missing from Imageshak -bastards lost or tossed them away - tossers!!

[AndisArt 2,068]

Great, thank you ver much

[SimFox 804]

Here is second part of the Lighting rig tutorial. It is long overdue for this a sincerely apologies. In the previous part that you’ll find few posts above I’ve briefly explained how rig works, described default one it weakness and made a case for a new design. If you are not familiar with the issue I suggest you read through it to be on speed with the discussion to follow. We left with the design of the sample Sun/Sky rig. Now I want to elaborate a bit on that, introduce alternative light sources, say few words on Low/High dynamic range light and, the most important part, to speak of setting global illumination solution – the thing that brings all this to life. IES SUN and SKY used in the rig set up in the first part are extremely bright at their default values – your entire scene will be just white. But there is a bit more to it… Unlike standard light where white tops at RGB 255,255,255 (or 1.0 in different system) High Dynamic light sources (as IES ones or MR SUN/SKY) can go above RGB255,255,255 (or 1.0) depending on bit depth even millions time higher. You basic monitor, though displays in same old RGB range of 0-255 per channel (8 bit), although some better model will be using 10/12bit color processing that effectively can shift the entire range up or down. So if this is a case what is a point in that High dynamic range? We can’t see white beyond 255,255,255. The answer is that although those numbers are not seen as such they are still used in calculations delivering much more realistic picture. Good example of it could be found in troubles many people trying to export dark colored buildings have – they tend to turn just totally black while in real life “black” even in the shadow isn’t totally black this is cause all the light sources in RL are High Dynamic ones. Another typical example of the workings of high dynamic lights is how their “bleach” colors. Not just put one flat white spot as over bright Low dynamic light source on say white surface, but exponentially (and smoothly) reducing saturations of colors.  To take advantages of High Dynamic range lights and not to get just white render window you would need to switch on something called Logarithmic Exposure control. This set of calculations in a way emulate the workings of human brain equalizing and adjusting brightness and saturation levels. These controls should be in Environment Window (max menu: Rendering->Environment). I said Should cause if you have installed Bat4Max according to supplied instructions they wouldn’t be there if you check… The reason is the peculiar mistakes made in scripts. Luckily there is rather easy way around this problem. Just copy entire content of PlugCFG folder in you MAX installation directory to the BAT folder. Done this you’ll gain access to the Exposure control features. In Exposure Control Rollout of Environment window select Logarithmic Exposure Control  and in Logarithmic Exposure Control Parameters roll-out tick the Exterior Daylight option. Another thing you may use in order to get better color match to the Game environment is to enable Color Correction. Tick the option and then click on color swatch next to it and put following values Hue 128, Saturation 25-50 (try settings in the range to see what fits better), Value 255.This will allow you to use IES SUN/SKY at their default values. With introduction of MAX9 new options to set your SUN/SKY combo become available – MR (Mental Ray) SUN and MR SKY. These, like IES ones are high Dynamic. Also they would REQUIRE you to use Mental Ray as you rendering engine – which is a good thing as it is much faster and better then Scanline. The structure of Lighting Rig made of MR Sun and MR Sky is identical to one in part I. At this point I would need to make one semi correction to the Rig set in the Part I of this tutorial. To be absolutely correct the Sky should be positioned in the same manner as the sun. Why then I say Semi with correction? Well the issue is that for some reason when you set rig in separate file that later X-Refed into the file with your model during the export MAX for some reason calculates SKY as being vertically set anyway. So in effect The settings of Part I are what is working… But I thought to mention this issue so that you would know the CORRECT way even if it doesn’t appear to work in this particular circumstance. OK. Let’s talk now about the core of this lighting system – setting Global Illumination Solution – calculations that produce properly illuminated scene. If you try to render something without employing such a solution your scene still wouldn’t look right. Cause without it Render would only take in account the light that falls on object from either sun or sky. Light doesn’t bounce (like in real world) from the surface it hits. This results in total darkness in the spots covered from exposure to both Sun and Sky and generally produces much darker picture.  Three different options available to people with MAX. Light Tracer, Radiosity and Final Gather. The later one is Far faster and more advanced, but requires you to use Mental Ray as your rendering engine. The difference is so huge that I don’t see any point of talking of first two. So the first thing we should do is to set our rendering engine to Mental Ray. To do so go to Rendering -> Render (or just press F10) in the tab titled Common go all the way to the bottom and in the Assign Renderer roll-out chose Mental Ray Renderer in Production menu. Done that you’ll notice that now you have different Tabs in your Render Scene window. To get you global illumination to work you would have to turn on Final Gather (not the Global illumination – sounds confusing but there you have it… bizarrely Mental Ray is a German product. , you would expect more logic from something coming from that land).The settings you will have to choose will depend on the version of MAX you’re using. It would be pointless to list all of them here. Just go to your MAX help and tutorials all the needed information is supplied there. Apart from the tutorials in MAX Help here are two links from Superb Polish based but international in nature 3d site called Evermotion.org (it is all in English): For people with MAX7-8: Various Settings Of FinalGather For people with MAX9 (I strongly suggest to use MR Sun/Sky combo): Mental Ray SunSky Settings tutorial If any of you have any questions – feel free to ask!

[AndisArt 2,068]

Great, thank you  

I followed your instructions, but when I render the pic is almost black. When I increase the Sky from 0,04 to 0,4 it looks like this: 

When I additionally increase the Sun from 900 to 9000 it looks like this: 

What might I do wrong?

And what are those weird shadows in the render? 

Also I'm wondering how you can edit existing rigs. 

Is it neceassary to change the assigned renderer for Material Editor and Active Shade as well?

Many Thanks!

[SimFox 804]

what sort of sky/sun you use?

Do you use any exposure control?

The color splotches are the result of low settings of GI (or Final Gather). What version of MR/MAX do you use?

[AndisArt 2,068]

I fixed the issue with the darkness, I'm still not able to get the render quality right though. Here is what I get all the time: 

I tried different Sample (20,100, 500), different Min.-Max. Pixel (0,1/1,0 and 0,3-3,0), Filter (1 and 3), nothing helped. Do you have an idea? 

I use Max 7, here's what my options look like:

[SimFox 804]

Hm... I don't have MAX 7 and my options are quite a bit different (MAX9) but I'm sure that those circles you see are the photons. Do you have GI enabled? Could you open Caustics and Global Illumination roll-out and post it here?

BTW there is still something not quite right with your illumination levels. Your shadow falls completely into the black this just can’t be right. Have you read through the tutorial on settings for FG for early versions of MR? (like your one). It it is my last tutorial post on this page.

[AndisArt 2,068]

Which tut do you mean? The link? I followed all your insctructions from above.



I also found options for photons in the IES Sun:

[SimFox 804]

this one:

http://www.evermotion.org/vbulletin/showthread.php?t=42049