Lighting Problem ..
FilthyAppetite
Posts: 149
Hi,
So I'm experiencing a lighting problem, currently using Iray.
The problem is, my interior light source is visible in some shots.
Setup, undercounter light, if set to the brightness to cast the correct shadows etc, it washes out.
What I would like to do, if possible.
Set the current light to what I need it to look like in the scene, to protray it as a light that is bright enough to cast the shadows and be looking right.
Support that with a geoshell of the light and set it to the brightness I need, but then can I hide the geoshell and still have it's light property effect the scene?
I only ways to hide the object while looking at it, or hide it when the scene is rendered, but not hide it and let it work as a light.. heh..
Anyone know what I mean by this, or what I'm trying to accomplish?
thanks for any help..
<-still newb..
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Comments
Iray can't really hide the lights like 3DL can.
As for the 'washing out'...what are your settings? (both light and tone mapping)
I havent tried past default, but having to set lights at and around 5million causes some funk :/
If you have visible light sources in your scene, the way to do it is to expose to that light source, not go through some complicated gymastics trying to fake it.
That's where Tone Mapping comes in.
Look on your Render Settings tab and find the entry for Tone Mapping.
The default Tone Mapping is set for an outdoor shot in pretty bright, direct sun. That's not going to work for what you are trying to do. You are going to need to change your Exposure Value (normally I would suggest altering the indivdual settings, like ISO, F/Stop, etc; but you identify as noob, so I want to keep it simple), bump it down one step at a time until you are getting the Exposure you want.
It might take longer to render, but you will get the effect you are looking for and won't need to crank up your lights to ridiculous values.
Once you get comfortable with that and maybe do a little research into the settings, you can try fine tuning with ISO, F/stop, Shutter, etc.
Cool, I'll definatley look into that..
thanks. :)
Noticed a new to me, thingie too..
The distant lights seem to penetrate objects ... I dun like it.. not sure why, but for an interior scene, trying to get shadows cast all the time from every window, it makes the ambiet light where there should be done way brighter.. like if I remove the ceiling, it has no effect as putting it back on..
is this odd, or perhaps a bug?
I don't use the distant light in Iray. I recommend you don't either. :)
What do you suggest then?
I thought I ran across a sun system, or it was in another program... prolly why I cant find it again...
I guess I could use a spotlight, move it really, really high and set it to some insane brightness and see what happens I guess.
Yes and no. Regardless of where the distant light is placed in the scene, it is treated as an source infinitely far away, so that the light rays are parallel. Among other things, this means there is no falloff of the light with distance, as there is with the other light types. All objects, regardless of distance from the light, have the same illumination. It also means that only the direction of the light is important. Because of this, the light source may come where you least expect it. This may be what's causing the effect you're seeing. (Hard to tell what's happing; you might want to post a picture of your setup.)
Following are simple test renders that show the effect of solid geometry placed in the direction of the rays. Note that the distant light "fixture" is actually right under the character, while the geometry plane is placed a few meters away. See the render with the red background (to show the plane). It casts a solid shadow against the figure. No light is getting through this object.
The two other examples show the effect of modifying the shader of the plane. Examples show how you can apply a transparent color to it, and now you have a colored gel. Or apply an alpha transparency, and you have a scrim, where you see the distinct pattern of the scrim material.
Cool,
those renders are using the distant light correct?
Looks like it would be a cool use for outdoor effects... atleast that's what I'm gathering.. as to use that effect indoors might mean tons and tons of light blockers with shading effects.
You can always tell a distant light: the "fixture" appears as three arrows, which point to the direction of the rays.
How much light you need depends on the scene. It's quite easy to create an indoor scene using only two walls and no or partial ceiling. This is how scenes are shot on a movie set. 3D art can be produced in the same way. Many of the better constructed indoor scenes allow for the removal of walls and ceiling, and Iray itself provides a way to "slice off" geometry if it's blocking light. For the latter, look for posts here on the Iray sectioning plane feature.