Efficacy scale
Efficacy scale
Hello everyone:
That difference theory and practice are between:
. have activated
. Not be activated Efficacy scale on a EMITTER
Thank you.
That difference theory and practice are between:
. have activated
. Not be activated Efficacy scale on a EMITTER
Thank you.
- Bogey Jammer
- Posts: 44
- Joined: Mon Aug 13, 2007 12:37 am
- Location: France
I never tried to desactivate the efficacy scale, but turning it on let you to set up realistically a lamp depending of the lightning technology.
eg for a 150cm fluo tube of 56Watt, I put 56 for the power and 80lm per watt (standard value for a fluo tube)
An incandescent bulb has 15 lm/W, but to get a realistic simulation, I think the filament must be the emitter and be geometrically accurate...
Sometime I take a look in lightning gear catalogs to get some interesting data.
eg for a 150cm fluo tube of 56Watt, I put 56 for the power and 80lm per watt (standard value for a fluo tube)
An incandescent bulb has 15 lm/W, but to get a realistic simulation, I think the filament must be the emitter and be geometrically accurate...
Sometime I take a look in lightning gear catalogs to get some interesting data.
- Borgleader
- Posts: 2149
- Joined: Mon Jun 16, 2008 10:48 am
Here are some other values which may come in handy. If you want take the same mesh and try different values to see what result you get. It may give you a better idea of how this affects your render.
Blendigo Manual wrote:candle - a nominal 40 W --- 0.3 lm/w
5 W tungsten incandescent --- 5 lm/w
40 W tungsten incandescent --- 12.6 lm/w
100 W tungsten incandescent (110V) --- 16.8 lm/w
100 W tungsten incandescent (220V) --- 13.8 lm/w
quartz halogen (12-24V) --- 24 lm/w
5–24 W compact fluorescent --- 45–60 lm/w
34 W fluorescent tube (T12) --- 50 lm/w
32 W fluorescent tube (T8 ) --- 60 lm/w
36 W fluorescent tube (T8 ) --- up to 93 lm/w
28 W fluorescent tube (T5) --- 104 lm/w
5 W white LED --- 22 lm/w
Yes it does.tony wrote:Efficacy scale cancels gain?
Bogey Jammer, you are setting power_drawn correctly and are right about the required realism in modeling. But efficacy_scale is the percentage of power_drawn that is actually emitting light. As an example, light bulbs spend most of the wattage into heat (around 80% !), so for that technology you want to set efficacy_scale to (around) 20 (%): that's the quantity of the total iniyial power this technology actually translates into light.
edit: now that you are two guys showing Lm/W I have doubts, but I shouldn't I guess
obsolete asset
- Bogey Jammer
- Posts: 44
- Joined: Mon Aug 13, 2007 12:37 am
- Location: France
- PureSpider
- Posts: 1459
- Joined: Tue Apr 08, 2008 9:37 am
- Location: Karlsruhe, BW, Germany
- Contact:
Thank you all for your responses.
I think I understand the theoretical foundations of simulation of real lights through the Efficacy scale parameters.
But I have some doubts:
1. blackbody mode, so that the simulation is real Is that value has to take temperature? 5000 (default)?
2. that way the issuer must have: spherical, cylindrical, flat, etc..
3. that size should have the issuer. He found what he says the wiki
Note: The ‘power drawn’ is over the whole emitter surface, not per unit area. So a bigger mesh area or a scaled one with the same setting means comparatively less light output as seen by the observer. For ‘uniform’ emitters the spectral radiance values to use will be quite large - say 10^8.
For example:
In my house there is a 3mx3m room with a lamp on the table. The lamp has a bulb 40-Watts.
What shape and size I have to give the issuer to enlighten like my lamp?
Tonemap: Reinhard, Linear, Camera?
Thank you.
I think I understand the theoretical foundations of simulation of real lights through the Efficacy scale parameters.
But I have some doubts:
1. blackbody mode, so that the simulation is real Is that value has to take temperature? 5000 (default)?
2. that way the issuer must have: spherical, cylindrical, flat, etc..
3. that size should have the issuer. He found what he says the wiki
Note: The ‘power drawn’ is over the whole emitter surface, not per unit area. So a bigger mesh area or a scaled one with the same setting means comparatively less light output as seen by the observer. For ‘uniform’ emitters the spectral radiance values to use will be quite large - say 10^8.
For example:
In my house there is a 3mx3m room with a lamp on the table. The lamp has a bulb 40-Watts.
What shape and size I have to give the issuer to enlighten like my lamp?
Tonemap: Reinhard, Linear, Camera?
Thank you.
blackbody is a temperature in Kelvin, yes. Though where ever you see "light temperature", that's not a perfect match, just the closest you can get
(For example, our sun has a temperature of about 5777K)
2. ??? - do you mean, Indigo needs more primitives? That would be nice indeed
3. ???
A 40W emitter mat on a 9m² plane...
and the Lm/W should be found on the bulb itself and/or on it's package...
(For example, our sun has a temperature of about 5777K)
2. ??? - do you mean, Indigo needs more primitives? That would be nice indeed
3. ???
A 40W emitter mat on a 9m² plane...
and the Lm/W should be found on the bulb itself and/or on it's package...
Hey tony, i think you are making yourself to much worries.
1. there is no wrong temperatyure, it depends on the light source you want to design. Very hot iron will have a "cool" temperature (redish colour), while for instance a camera flash will have a high temperature (blueish tint).
2. it's up to you. Probably it will have the shape of the real emiter. Take a real object as reference if this is of concern.
3. a realistic size. For a given power, the result will be different if a bulb emits light, or if a filament within the buld emits light. Obviously the power consomption is from the filament, not the bulb. Shape and size: a filament.
You do not have to use this or that tonemapper, it's up to you, again.
1. there is no wrong temperatyure, it depends on the light source you want to design. Very hot iron will have a "cool" temperature (redish colour), while for instance a camera flash will have a high temperature (blueish tint).
2. it's up to you. Probably it will have the shape of the real emiter. Take a real object as reference if this is of concern.
3. a realistic size. For a given power, the result will be different if a bulb emits light, or if a filament within the buld emits light. Obviously the power consomption is from the filament, not the bulb. Shape and size: a filament.
You do not have to use this or that tonemapper, it's up to you, again.
obsolete asset
- Borgleader
- Posts: 2149
- Joined: Mon Jun 16, 2008 10:48 am
Who is online
Users browsing this forum: No registered users and 27 guests