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    Exact effect of a 40 watt fluorescent light

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    • andybotA Offline
      andybot
      last edited by

      hehe, well, there's vray and then there's vray... Some images you may see online are using vray for max where you can have super high-poly components, better GI and HDRI options, and a number of other tricks that the pros use. I would suggest looking at some of the tutorial videos that are available for vray for sketchup and you may find some tricks to help you in your renderings.

      http://charlottesvillearchitecturalrendering.com/

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      • N Offline
        nomeradona
        last edited by

        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

        visit my blog: http://www.nomeradona.blogspot.com

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        • john2J Offline
          john2
          last edited by

          @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.]

          Sketchup Make 2017 (64-bit), Vray 4.0 , Windows 10 – 64 bit, corei7-8750H, 16GB RAM, Nvidia GeForce GTX 1050Ti 4GB

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          • V Offline
            valerostudio
            last edited by

            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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            • V Offline
              valerostudio
              last edited by

              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.


              Maxwell.jpg


              Vray.jpg


              Model View.jpg

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              • andybotA Offline
                andybot
                last edited by

                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.


                Vray-problems.jpg

                http://charlottesvillearchitecturalrendering.com/

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                • V Offline
                  valerostudio
                  last edited by

                  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 πŸ˜„ ?

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                  • andybotA Offline
                    andybot
                    last edited by

                    @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 πŸ˜„ ?

                    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.

                    http://charlottesvillearchitecturalrendering.com/

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                    • R Offline
                      rspierenburg
                      last edited by

                      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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                      • andybotA Offline
                        andybot
                        last edited by

                        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.


                        vray2_6d5_03.jpg


                        vray2_6d_test4.jpg

                        http://charlottesvillearchitecturalrendering.com/

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                        • V Offline
                          valerostudio
                          last edited by

                          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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                          • andybotA Offline
                            andybot
                            last edited by

                            @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)

                            http://charlottesvillearchitecturalrendering.com/

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                            • pilouP Offline
                              pilou
                              last edited by

                              There is not a tool for that in Light Up ?

                              Frenchy Pilou
                              Is beautiful that please without concept!
                              My Little site :)

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                              • V Offline
                                valerostudio
                                last edited by

                                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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                                • N Offline
                                  nomeradona
                                  last edited by

                                  if its using wattage then biased render cant replicate that.

                                  visit my blog: http://www.nomeradona.blogspot.com

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                                  • N Offline
                                    nomeradona
                                    last edited by

                                    andy that is cool tests.

                                    visit my blog: http://www.nomeradona.blogspot.com

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                                    • john2J Offline
                                      john2
                                      last edited by

                                      what is biased rendering and unbiased rendering??..and andybot. awesome effect. πŸ‘

                                      Sketchup Make 2017 (64-bit), Vray 4.0 , Windows 10 – 64 bit, corei7-8750H, 16GB RAM, Nvidia GeForce GTX 1050Ti 4GB

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                                      • V Offline
                                        valerostudio
                                        last edited by

                                        I think this article has the basic answers to this question.
                                        http://galaxycityradio.com/2012/01/04/biased-vs-unbiased/

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