How to make linear point light work in Iray?

SPadhi89

Hi,

I want to make a campfire scene. I have made the necessary arrangements of the campfire, placed props and imagined woods in the background. I can work the fire in photoshop postwork. BUT here is the main issue... 

I am trying to light up the scene using a linear point light, as if the scene is being lit by the light from burning fire. I have used Dome and Scene (a HDRI whcih works superb , but lights up people from one direction only) , increased the Lumens to 50K, changed the fallout thing etc.. but still it doesn't seem to be working.. the area that the light covers is very less. How to fix this? I want the lit-up area to be more, at least the face of the people around the fire should be visible.. It was easier to do with 3Delight, but I want to use this idiotic IRAY thing. 

All help is appreciated.

Thanks!

Sylvan

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

SPadhi89

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

Cool, thanks! Let me try and see how it works. In the meantime I've read this inverse square falloff of point light in Iray.. what does that mean? Does tht mean this particular feature can't be used in Iray renders?

 

Richard Haseltine

spd0089_3293e62e1f said:

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

Cool, thanks! Let me try and see how it works. In the meantime I've read this inverse square falloff of point light in Iray.. what does that mean? Does tht mean this particular feature can't be used in Iray renders?

Yes, light in Iray behaves realistically - which means that as the distance from the source doubles the intensity falls by a quarter, trebles and it falls by a ninth, and so on. The options for no or linear fall off (double distance, half intensity, treble distance, one third intensity) are not available.

SPadhi89

Richard Haseltine said:

spd0089_3293e62e1f said:

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

Cool, thanks! Let me try and see how it works. In the meantime I've read this inverse square falloff of point light in Iray.. what does that mean? Does tht mean this particular feature can't be used in Iray renders?

Yes, light in Iray behaves realistically - which means that as the distance from the source doubles the intensity falls by a quarter, trebles and it falls by a ninth, and so on. The options for no or linear fall off (double distance, half intensity, treble distance, one third intensity) are not available.

SAD :(

But, Thanks for clarifying that :)

SPadhi89

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

hey, thanks! I understood and I will keep trying that. I did a test render for a torch. followed your steps and was able to light up the scene.. but again, when I made the flame emissive, it turned into an opaque object and in the render it doesn't look like fire at all. Please refer to the attached pictures. What to do to make the flame transparent.. I can create flame/fire in photohshop.

 

Richard Haseltine

spd0089_3293e62e1f said:

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

hey, thanks! I understood and I will keep trying that. I did a test render for a torch. followed your steps and was able to light up the scene.. but again, when I made the flame emissive, it turned into an opaque object and in the render it doesn't look like fire at all. Please refer to the attached pictures. What to do to make the flame transparent.. I can create flame/fire in photohshop.

make sure that the blacka reas of the opacity map really are black, and apply the flame's colour or opacity map to the emissive colour so that the darker areas don't glow.

SPadhi89

Richard Haseltine said:

spd0089_3293e62e1f said:

Sylvan said:

You could create a new primitive and choose a sphere. Give that a emissive Iray shader from the base shaders that come free with DAZ. Set Luminence Units to lumen (lm) and manually crank up the lumen to a very high number (I believe 50.000 or 500.000, just experiment what works best for your scene). You can either change emissive temperature to a lower number to give it a warmer colour, or change the emission colour. Resize the sphere to your liking and place it in the middle of the fire. Better even, make your flames emissive for a more realistic look.

A set that I've been using lately is this one: https://www.daz3d.com/the-torch-and-construction-kit
Very versatile and the flames look awesome.

 

hey, thanks! I understood and I will keep trying that. I did a test render for a torch. followed your steps and was able to light up the scene.. but again, when I made the flame emissive, it turned into an opaque object and in the render it doesn't look like fire at all. Please refer to the attached pictures. What to do to make the flame transparent.. I can create flame/fire in photohshop.

make sure that the blacka reas of the opacity map really are black, and apply the flame's colour or opacity map to the emissive colour so that the darker areas don't glow.

hey, thanks!

I followed your instructions and got everything set. Just need to play with the dials to get the correct effect!

benniewoodell

50K might be too small a number, I'm usually in the 200K to 1 million range when I'm lighting. Boost that and try it. 

SPadhi89

benniewoodell said:

50K might be too small a number, I'm usually in the 200K to 1 million range when I'm lighting. Boost that and try it. 

Yeah true, I learned that while fllowing the previous instructions. Thanks!