Hello all. Time to present : Arnaudv6, nice to work with you
I’m currently on a project for my work: rendering a saloon.
I’d like no artifact in my lightning: thus I modeled lamps.
Problem is I can’t manage them to (indirectly) lighten the roof also…
I wished the ground could set light and materials so roof is “white”.
I have set some ray mirror, but ultimately, I don’t need a mirror aspect :no:
Task is quite simple, but is it possible ? Hope I’m clear.
Attached is a simplified model. Sure you have ideas.
Arnaudv6
Sounds like you are looking for indirect lighting.
When an object bounces light from a lightsource back, lighting other objects.
Its a 2.5 feature.
Also various external render engines support indirect lighting, but require a seperate setup.
The least desireable solution is radiosity, it requires a dense meshgrid and lots of computational time.
You could also fake the ceiling emiting light by using a arealight with low emmision, or you could subdivide the ceiling and vertexparent pointlights to it.
There are many ways to achive what you are looking for and lighting a scene and setting it up for render is an art itself which requires some dedication. And getting great results in a reasonable rendertime usually justifies the time spent on it
Hello Arexma.
I had just noticed a fairly complete answer to surreal5335’s question in previous thread White material appears grey in render
Thank you for your answer! First described method is the one fulfilling my requirements I guess. Since I wanted to avoid emitting trick.
Tutorial video is blocked by my “security” proxy at work…
But I will have close look to 2.5 features. I want to use it since a few months, but didn"t dare. mostly because of a detail: the new grey background is too dark to me… Wich I shall be able to change.
Thank you so.
Arnaudv6
Basically you turn off mirroring for your material.
Give it a slight amount of emmision.
Switch to the world tab.
Turn on Ambient Occlusion and Environment Lighting, switch to Approximate under Gather and then turn on the freshly appeared Indirect Lighting. Choose the amount of Bounces and set the Sampling passes for Approximated Gather.
Then you got a first basic result of what you want.
Tweaking said settings and the energy of your lightsource and the amount of light emited back by the material should be plenty of control to set the right mood for your room.
Thank you Arexma: I’m playing around right now!
Cool stuf. I just realized that in my head “horizon” and “environment” were the same, which is not the case :
environment are surroundings objects we created… right ?
Emision is not really required uh ? I always consider it as a “trick”.
Shading’ Ambient parameter, is the only way to control the “amount of light emited back by the material”, right ?
I am still new at this also. Here is simple saloon light setup example. I used 2 Emit object. One is the window and other the spot light circle hanging from ceiling. I made it blown out white. They don’t light up the scene. For lighting there are 3 lights; A and B are area light, and C is spot. AO is included. A light simulates the window light. B light simulates bounced floor light from window and overhead spotlight. Note how area light works by the window. It does not light up behind the area plane. But it does lights up doorway opening nicely.
By the way your room model walls had normal pointed the wrong way away from room interior.
ridix scene is a beautiful example how to fake nice indirect lighting and global illumination.
Without AO I am sure you can use the spotlight with buffershadows only and get rather believable looking results without raytracing at all.
And yes, emit is rather trick-ish IMO.
It makes an object lighten up, but not really emit anything.
You can try in 2.49 make a scene with a plane and a cube on it. make the cube emit light and add no lights. In a render the cube will be visible as it “emits” light, but it will not lighten anything.
However it is nice to make blown out light materials, or lighten up materials in a scene in a way global illumination would do.
If you do the same in 2.5 and only set approximated gather and turn on indirect lighting, you can see that the emit value now got a real use and starts to emit light and lighten up the plane it sits on.
So in 2.5 emit got a real light feature
Shading>Ambient: It is the percentage of Ambient light (world setttings) that is reflected by a material.
In 2.5, there’s a feature called ‘mesh lighting’ that works really well for certain things. I am not sure how to use it, but if you go into the 2.5 release notes, go to the bottom of the page, and click the ‘tutorials’ link, it will take you to a video tutorial describing the process, as well as some other features of 2.5.
Thank you Arexma, Ridix and Modron for your analyze, pictures and tips.
I’m really sorry about providing no picture for my case
But I understood your ways I think.
At least I won’t try being too purist: I think I’ll finally use both emission and “non existing” lights.
Plenty of things have changed with 2.5th version! Some I don’t know why.
I jumped for this lightning matter, but still haven’t found controls for cylindre creation for instance :mad:
