[whoek22]

Dear fellow su

I have a problem with my emitters and thought maybe one of you could help me out. I have assigned an emitter to the headlights of a car, parked in front of the garage. Now the emitter works perfectly and i have set up an evening surrounding. The only thing is that the emitter wont reflect on the door of the garage, for what is normal in the real world.

Does anybody know what im doing wrong? I have the following settings:

Scene: emitter_2m

Type: emitter
Watts: 120
efficacy: 55
Temp: 5000K
Roughness 100%


Greetings

Wouter

[JDHill]

The first thing is to confirm that your emitter is emitting light, so before doing anything else, disable the environment and check that. Provided that everything is okay there, the second factor is to remember that a headlight is not a simple emitter, it is a light with a reflector and lens. If you want light to shine from this modeled headlight in a similar way, you either need to create a setup approximating the real thing, or find an IES file that mimics what it produces.

[whoek22]

Hi JDHILL,

Thanks for your reply. I have checked everything and my emitter is indeed emitting light. Lets say if i dont want to use an IES file and want to work with an emitter he, what could be the right setup in this case? I would like to work with emitters more just because its easy to apply.

Does an emitter reflect light on an indoor setting? lets say an emitter above a table reflecting on a wall?

[JDHill]

Emitter materials emit light from the faces to which they are applied, according to the normal direction of those faces. How they reflect is not determined by the emitter material or geometry, but rather any geometry from which they are reflected. This is the same as in real life. To illustrate, let's take the question back to reality and try a variation on your original garage scenario, but rather than shine the car's headlights at the garage, stand in a similar place holding a normal incandescent light bulb in your hand. Some light will fall on the garage door, but it will be diffuse with no real visible pattern. Now point a flashlight, or one of the car headlights, at the garage -- things will work the same in Maxwell. And actually, in the case of a headlight, it's likely that you can't even directly see the bulb; rather, it is housed in a second, smaller reflector, which points backward, such that the light you see has already bounced off two reflectors, before going through the front lens. Here is a good example of a flashlight modeled using these principles.

[whoek22]

Thanks JD,

Helpfull answer!

I have only 1 more short questions,

I can't find the EV chart that is supposed to be at the end of the camera documentation of sketchup.

I want to do some things with emitters and IES for nice nighttime renders. I just want to have a look at what environment and camera settings are best to show emitters and lights

greetings

wouter

[JDHill]

The EV chart is all the way at the end of the plugin's (PDF) manual, but since Maxwell's camera is realistic, the list is actually just a copy of information you can find here: Exposure Value.