Vray gpu 5 dome light, affect diffuse, affect specular and affect reflection

V-Ray V-Ray for SketchUp General
1

Hi Konstantin

When do you increase or decrease these values???

I did an exercise and it is not affect the diffuse, it affects the global ilumination.

when i increase reflection parameter it increase automatically the specular

is it possible to have a different value for 1 and another value for the other??

This kind of question is what sometimes helps to understand better the software

I really liked these option

But When do you use it?

What kind of aplications does it have?

Thanks in advance

Best regards

2

Hi Luis,

These controls are useful for studio lighting for cars or products. See this example

In this case many area lights are needed to shape the product, some of which have diffuse contribution turned off so that it only affects reflections

Keep in mind that changing these settings is not physically accurate and breaks physically based rendering, only use them when it is required.

In (real)photography, to get around this issues of having many lights on a product they will paint the lighting and reflections in Post as they don’t have such controls.

Best,
Muhammed

3

Hi Muhhamed

Thanks For taking your time with the question and the example.

I Would like to ask you about this, when i increase the affect diffuse it affects the global ilumination?

I did a test

1.5 in affect diffuse looks really bad

1.25 looks a bit better

1.1 looks really nice, bring a bit of global ilumination and i dont get burned anything.

Incrising a bit gives you a better global ilumination

Sometimes when i do a render inside in a big garden the lighting does not match what it should look in real life

Vray gpu struggles to achive a really nice light or global ilumination inside in a big dense garden.

Seems like vray gpu can not bring enought rays inside the dense garden.

The last Muhammed i use a lot composite in VFB, sometimes i increase just a bit reflection, decrease specular, decrease lighting and increase global ilumination.

with affect diffuse can i increase a bit the global ilumination as i do with VFB

I dont touch affect specular neuther reflection

I understand your point too, change this values is not physical correct, but if i change just a little bit i believe i can get more light in very specifical situations

Thanks Muhammed

Best regards

4

Hi @luisgamino2

Affect diffuse, indeed affects Global illumination on vegetation. Feel free to use on your vegetation if you wish
As long as it looks better

For vegetation often times you need extra effort in post to make it look right, this is normal

All the best,
Muhammed