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Dear Group
I am attempting to gain some understanding of the VRayLight object. I have read through the User's Manual and I have searched through the archives of this forum to gain some insight. In particular, I have come across the following thread:
http://www.chaosgroup.com/forum/phpB...raylight+units
The aforementioned thread was based on an earlier version of VRay. In this thread, it is mentioned that VRay uses generic units and that 1 unit is assumed to equal 1 meter. For the lights that I am experimenting with in version 1.5, I am using the intensity unit luminous power (lm) due to its independence from the size of the object. In the Vray manual it states:
"Intensity Units - allows choosing the light units. Using correct units is essential when you work with the VRayPhysicalCamera. The light will automatically take the scene units scale into consideration to produce the correct result for the scale you are working with."
From this, I would assume that the user would not have to perform any conversions because VRay automatically makes the necessary conversions during the rendering process. I decided to create a small room that measures 120" x 120" (10'x10') to perform a lighting experiment. For my scene, 1 unit = 1 inch. I set the luminous intensity to 1500 lm (a standard 100W light bulb) and here is the result:
As you can see, everything is washed out by the light. The physical camera is set to ISO = 250, fstop = 2.8, shutter speed = 1/30s. I decided to scale the intensity light down by 0.0254^2 (converts in^2 to m^2) to 0.96774 lm. Here is the result:
As you can see, everything seems to be in much better range as compared to setting the luminous intensity to 1500 lm. However, this contradicts the User Manual, which states that the scene scale is taken into consideration. Can anyone provide any insight as to what's going on?
Marc
I am attempting to gain some understanding of the VRayLight object. I have read through the User's Manual and I have searched through the archives of this forum to gain some insight. In particular, I have come across the following thread:
http://www.chaosgroup.com/forum/phpB...raylight+units
The aforementioned thread was based on an earlier version of VRay. In this thread, it is mentioned that VRay uses generic units and that 1 unit is assumed to equal 1 meter. For the lights that I am experimenting with in version 1.5, I am using the intensity unit luminous power (lm) due to its independence from the size of the object. In the Vray manual it states:
"Intensity Units - allows choosing the light units. Using correct units is essential when you work with the VRayPhysicalCamera. The light will automatically take the scene units scale into consideration to produce the correct result for the scale you are working with."
From this, I would assume that the user would not have to perform any conversions because VRay automatically makes the necessary conversions during the rendering process. I decided to create a small room that measures 120" x 120" (10'x10') to perform a lighting experiment. For my scene, 1 unit = 1 inch. I set the luminous intensity to 1500 lm (a standard 100W light bulb) and here is the result:
As you can see, everything is washed out by the light. The physical camera is set to ISO = 250, fstop = 2.8, shutter speed = 1/30s. I decided to scale the intensity light down by 0.0254^2 (converts in^2 to m^2) to 0.96774 lm. Here is the result:
As you can see, everything seems to be in much better range as compared to setting the luminous intensity to 1500 lm. However, this contradicts the User Manual, which states that the scene scale is taken into consideration. Can anyone provide any insight as to what's going on?
Marc
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