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Set build for lighting

Here are some things to bear in mind when building sets which ultimately will be lit.  Most of this advice is relevant to advanced lighting and to basic lighting. Advice which relates only to advanced mode lighting is in blue.

If you read nothing else read that which is in  red

Please bare in mind that what is understood here as “advanced” in reality has been common on other environments for quite some years.

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SL can produce extraordinary effects with care
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When it all comes together

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Colours and textures

Please remember that on a computer black is totally black, a black surface  reflects no light and therefore will always render as total black, essentially you have a black hole in your build.  Its better to use a dark grey with a small amount of highly desaturated blue instead of black, this works well and more nearly simulates a black surface in the real world.  In addition a small amount of shine on the surface will help the surface to come to “life” and look far more visually interesting and realistic.

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The effects of advanced lighting and a little shine on the stage surface

Similarly white on a computer is rendered as a white which has no counterpart in the real world, a totally white surface reflects everything and makes it very hard for your viewer to generate  properly balanced image.  A pure white surface runs the risk of “burning out”.  Far better to use use a light grey or light cream colour, this is much closer to that which is seen in the real world.

A related problem is if two characters are close, one is mostly white and one mostly black, its almost impossible to light the scene so that details is properly visible in the blacker character without burning out the detail in the whiter character.  Please consider this if your design requires any sort of lighting and especially advanced lighting.

In advanced mode it is possible to add normal and specular maps which significantly add to the quality of the rendering.  A specular map marks areas on a surface which will reflect specularly (see note at the bottom to explain specular reflection)  Adding proper specular reflections significantly boost the quality of the rendering. 

Also its possible in advance mode to use normal maps.  A normal map controls how shadows and reflections are generated on a surface.  Using a normal map a totally flat surface can appear to have huge detail, as an example of this the ornate textures at ROH which adorn the auditorium if normal mapped would appear to pop out and be fully detailed and 3 dimensional, as you moved your camera over them reflections and shadows would move as though the surface high high detail but without the cost and lag issues of including a high detail mesh surface.  

Full bright

Full bright should be avoided except in a few very specialised areas.  What full bright does – and it does this in basic mode and in advance mode – is to defeat the proper operation of

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The rear backdrop is a properly lit object rather than full bright, notice how it properly moves into the background

the graphics shaders.  Your viewer normal takes into account surrounding lighting from the sun, moon, basic lights and advanced lights and the material properties in advanced mode and surface shininess in basic mode to correctly calculate the illumination brightness and colour to apply to each facet on  surface.  This boosts the 3 dimensional effect, boosts the realism and means that what is presented more closely relates to your real world expectations, this is important because its this which allows you to use your real world experience to correctly understand and interpret what it is your seeing.  Fulbright, when enabled, just illuminates the face at its maximum value. A fully full bright scene loses all 3 dimensional illumination cues and looks strangely flat, a full bright surface cannot react to incident lighting of any sort.

Full bright on parts of builds produces a weird effect should you ever turn the lights out, which of course has to be done if your interested in producing anything which is remotely realistic.  `Full bright on costumes has the same problem.  In General, full bright should not be used and given the improvements in viewer rendering its no longer necessary.

Built in lights

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The effects of built in lights, they are bright, light up the stage and yet fail to illuminate old

Lights built into sets should be avoided, such lights, seem, never to be scripted, are never controllable and always seem to be implemented as basic point lights.  If for some reason you feel the need to have them then contact me and i can provide a control script for them. Given how built in lights are usually set in advanced mode it makes the whole scene lighting exercise totally pointless. 

Number of lights and rendering

There are limits on the number of lights your viewer will actually render, in basic mode this is 8 in total with 2 reserved for the sun and the moon.  The number in advanced mode is higher but is far from infinite.  In both modes your viewer has to decide which lights it will render and which it will ignore, and hoe much of each to apply in the final render. This decision is based on the POSITION OF YOUR AVATAR from the light sources.  More distant light will be selectively ignored – this applies to both modes. This is one of the two reasons against face lights – especially in the audience.  Face lights in the vicinity of your avatar will be selectively rendered in preference to the lights on the set which of course and there to add drama and effects and clarity etc. to the scene.  This does mean thats it becomes almost impossible to know in advance what any one person in the audience might actually see, worst case they may see very little. It is possible to demonstrate this, sit in an audience surrounded by people wearing facelights, have attached lights enabled in your viewer, observe the lit stage, disable attached lighting and you will see the stage lights appear

The other problem with them of course is that they tend to illuminate everything and because they are attached usually to faces they twist and turn meaning the stray light they add to the set can twist and turn without warning and almost without limit, this can be very distracting.  they also tend to desaturate subtle lighting effect, reflect off shiney surfaces and totally screw things up.

They also can add to client lag.

Most of this also applies to stray lights in the theatre build or on set components hidden below stage, the light from these will leak everywhere and interfere with the operation of your viewer as it tries to produce a properly exposed final scene.

To a very large extent in a properly controlled environment the difference between basic and advanced lighting modes can be minimised such that viewing in both modes can produce a reasonable scene.

In summary avoid fanlights on stage and in the audiences, don’t build lights into your sets. don’t have stray lighting in the theatre build or in stray sets under the stage

Set positioning and size

Because the advanced lighting system tries to implement features and effects which you might find in three real work equivalents they have to be correctly positioned (basic mode lighting is more a case of turning them on and turning up their output)

The lights understand the stage surface, they know where it is, multiple stage surfaced in a production are a constant pain and have to be continually adjusted for.  They understand the stage centre, sets that are symmetric should be placed relative to this or if not then all symmetric sets should be positioned in a consistent fashion – then at least i can compensate once.  Sets that are positioned properly relative to this centre are far far quicker to set up for lighting than sets which are placed off centre.

The lights understand the bounds of the stage and can automatically turn themselves on and off as objects and avatars entire and leave the stage – for this to work however does mean that the sets must have a constant approach to this – the res most wall of the best must be the same for all the sets – or if there are exceptions then the exception re few. similarly if sets have a constant approach to their positioning on the stage then this significantly speeds up setting up the lighting g for a production.  As an example Spirit used around 6 target positions for the lighting,  Phantom had over 140.  The difference was spirit took just an afternoon to set up, phantom took weeks (Also the spirit sets had no full bright and no built in lights and so never needed to be modified in anyway)

As a general rule the advanced lights as their range is increased light a smaller and smaller area, this is to control how the lights spills out for anyone watching the advanced lights in basic mode.  this means that sets which extend far from the lighting source become progressively harder and harder to light as the set size increases.  This translates into more and more time being taken to set the lighting up – of course if basic mode wasn’t a consideration then they needn’t do this.

In summary, try to be consistent in your set placement, of they are symmetric then place them centrally, be consistent in their front back placement, limit yourself to only a few planes (front back positions)

Follow spots

Follow spots of anytime need to know your avatar position and how its moving.  the advanced lights use the tracker.  This communicates with the lighting and when a follow is set the tracker reports your position at some rate whenever that position changes, all other follow spots do something similar (without a tracker your depended on the sim reporting the position when it has time – the tracker improves performance) The tracker incidentally reports your avatar sit and crouch animation state and the lights will compensate for this – you do need to trigger a proper sit or crouch, just a sit animation but with your avatar effectively still standing isn’t sufficient. This i.e. because avatar animations never got properly integrated into SL

Similarly if you use animations which significantly change your avatar positions the follow spots (of any type) cannot follow you. Please consider this when you design animations and make sure that significant position changes are accompanied by an actual position change of your avatar.

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Follow spots, properly lit flats with and auditorium lighting turned on

Particles

Particle effects which cannot be though of as emitting light set them so non full bright, particles effects re fightable with advanced lighting.

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Other thoughts

Scripted objects triggered by touch are probably not wise to use because of the preponderance of light beams prime on the stage – these though should not interfere if their respective light is turned off and certainly for advanced lights they stop well short of the floor and do try to leave un blocked any target pose balls on the stage.  If you do have difficulty then press and hold CTRL-ALT-T to make your viewer reveal insole/transparent objects. CTRL-ALT-T to turn it off again

Finally

Advanced lighting is best viewed using a viewer which has its wind light set to dark – set wind light to Photo Tools no light on firestorm and on other viewers edit a wind light preset to remove the sun and the moon. It goes without saying that advanced mode should be selected in graphics / preference, however, its not necessary to set the quality slider to above mid but of course if you can and wish to then you can.

I encourage everyone to have the proper settings for rehearsals and performances, this lets you see immediately if you have face or body lights showing, it lets you see where the light is on stage so that you can go and stand in it rather to one side and in the dark which is far more common.

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backdrop full bright
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standing to just miss the light fall
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follow spots for MissM
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A set from bully at the Stonewall theatre, advanced and basic modes were to a first approximation indistinguishable, mostly down the level of control exercised

 

Face lights

So what’s the thing about face lights

Your viewer has a pretty hard job to do. Twenty or so times a second it has to generate a scene, move the objects, apply textures,calculate the lighting to apply to each polygon.  To see how many polygons that is ask your viewer to show wireframe.

There are two different algorithms it can use to apply the lighting to the polygons .  The one it uses in basic mode and the one it uses in advanced mode when advanced lights are used.  The first of these isn’t that efficient and your viewer is only capable of rendering 8 lights in total, two of these are reserved for the sun and the moon, leaving six lights. More than this can cause excessive client side lag.  The advanced algorithm, called deferred rendering is more efficient and can handle more lights, however, there is still a limit and your viewer has to decide how to apply this limit.  Usually this is decided based on the lights seen from your avatars position – not your camera position). if that isn’t enough your viewer must work out how to apply all of this and still end up with a correctly exposed image.

The problem with face lights are:

  • Virtually all of them aren’t using advanced lighting – they are using point lighting
  • They are often over bright and are applied multipully (6 face lights which is pretty common potentially ruin the scene for anyone else who is near), they dominate the scene and screw up the balancing of other light sources by your viewer.
  • They move and turn – this causes other lights to cut in and cut out as your viewer is trying to balance the lighting in the scene, for anyone watching this – this can be a very ugly effect.
  • They overload anyone in basic mode – all they see are the 6 closest face light rather than what all the work went into creating. Even in advanced mode there is an element of this.
  • Changes made to the rendering model some time ago cause basic lights to have a range far greater than that which is set for them so more polygons are included in the calculation to apply the light and other lighting effects can be overwhelmed.  And there is strong evidence to suggest that when your viewer is trying to balance the lighting in a scene it takes into account all lights it knows about, not just the ones it has decided to render (this is so that there aren’t significant exposure changes as the lighting mix changes), this implies that any stray lights and not just face lights can upset this task – for example at TOTH, lights under the stage and even on other stages are still having an effect on rendering on the main stage – this is not insignificant, your computer really has to perform these calculations for millions of polygons every second.
  • All of this adds, and can add seriously, to client side lag
  • They can completely overwhelm and even ruin a scene, especially if it was set up to use subtle effects.
  • The advanced theatre lights will give you effectively a face light better than any you could dream of.

These arguments also apply to basic mode lighting built into sets. None of these lights is ever switchable and, therefore, are always on. They then have all the negative impacts to do with scene rendering and client side lag.  Its best not to have them, if you do have them then make them switchable, lighting under the stage which are turned on have a big negative effect on everyones viewer performance!