Exact effect of a 40 watt fluorescent light
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@nomeradona said:
i dont know. the first image is very easy to achieve even in vray sketchup.. why dont you learn from the setting of the different guys here. Look for those MTM (mini the makings) download the pdf tutorials and see it for yourself. there is no quick quick stuff in learning. understand why these guys are doing them like that..
download all the MTMs here.. http://www.sketchupvrayresources.blogspot.com
well i have seen those mtms what i'm trying to achieve is that the fluroescent tubelights should give the same uniform light effect as that in real life. what i do to create uniformity is create a rectangular light to get that even lighting, and i just make my tubelights emissive. they dont have any lighting material[that have lumens, watts, etc.]
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You can make tubes and apply an emissive material to them, but you shouldn't use that emitter material as your light source because you will get unclean results. This is what I would do. Make the tube, apply an emitter materials set to something low like 1 or 2, place 4 rectangular lights around the tube facing out -set them to invisible and to not affect reflections. We use the rect lights to cast the lighting and the emitter to give the appearance that the bulbs are lit. I was under the impression you needed to exactly show the conditions a 40W bulb would produce, that is just not possible here.
As for VRay being the standard in arch/viz, that's due to speed and user base mostly and not accuracy. Dont get me wrong, I love working VRay, and I use it all of the time in my work, but there advantages and disadvantages to every renderer out there. It's best to download the Maxwell free plugin for SU and give a try. Use what works best for your needs.
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So here is my testing on this. I did a quick box model and created a cylinder with an emitter materials applied to it. In the Vray rendering the tube has 2 rectangular lights emitting the light and in the Maxwell version the might is emitting solely from the material on the tube.
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This is exactly illustrating the problem I have with vray. The edges of the area light create a shadow effect, you can see it in the end, and you can see a line along the floor too. This is why I want to have a linear ies type. Would make modeling fluorescent fixtures much simpler and better.
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Guess I never thought of that, you could grab and IES file for a tubular light. Andybot, if you have one, can you share with the class
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@valerostudio said:
Guess I never thought of that, you could grab and IES file for a tubular light. Andybot, if you have one, can you share with the class
?Well, that's just the issue - ies as it is currently implemented in vray is a point source. The ies profile would have to be "stretched" along the length of the tube for it to represent a fluorescent bulb. You can only get sharp shadows from an ies source currently.
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So with the model shown above, what effect would you get if you completely incased the tube in 6 rectangular lights? Sort of a Cubic light if you will.
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I played around with simple rectangular lights, here are some results. You can see the light pattern is different depending on how many facets you make with the rectangular lights. It ends up with a bit of a hotspot on the ceiling using 5 planes, I actually think the 3 planes turned out better. The thing I made different from what valerostudio showed above is that I made the rectangular lights much larger than the bulb in order to get a softer more spread out effect. I have the lights set as hidden in vray.
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Andybot, nice work. The thing that we need to disclaim here is that nothing we are showing you is the "exact" effect of a 40w bulb. I am fairly certain this cannot be done in Vray, unless I am wrong. You can give an light a Watts setting, but I dont think this is directly related to how a real bulb works. Someone correct me if I am wrong here.
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@valerostudio said:
Andybot, nice work. The thing that we need to disclaim here is that nothing we are showing you is the "exact" effect of a 40w bulb. I am fairly certain this cannot be done in Vray, unless I am wrong. You can give an light a Watts setting, but I dont think this is directly related to how a real bulb works. Someone correct me if I am wrong here.
Thanks!
Correct, this is all approximate and relative. With IES files, there is actually a relationship to real values, but even then, the render engine uses an approximation (biased) -
There is not a tool for that in Light Up ?
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I have no experience with Light-Up but I think only an unbiased rendering engine will give you "real" world results.
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if its using wattage then biased render cant replicate that.
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andy that is cool tests.
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what is biased rendering and unbiased rendering??..and andybot. awesome effect.
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I think this article has the basic answers to this question.
http://galaxycityradio.com/2012/01/04/biased-vs-unbiased/
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