Nomeradona Lighting Tutorials: Series 1

First of all I must say these lighting series tutorials were already posted before in different sites and forums, but I want to gather and catalog them again using this site. The lighting tutorials of yours truly are everywhere, but never they were put together in one package. It is my attempt therefore to republish them again. Of course I will also put the sites where they were shared originally.

A. Interior Lighting foir beginners with Vray SketchUp 1.05.30

This tutorial was the very first tutorial of Nomeradona with VraySKetchup. It was originally shared at asgvis.com and  www.cgpinoy.org forums. Although this is an old tutorial, I think the process is still applicable even with any Vray version.

Here it is

09 February 2009 

Software use: Google SkethUp 6.0, VraySU 1.05.33

Step 1. The original Sketchup Scene.

Download the Scene HERE or HERE.

Step 2: Clay Render 

Here is the clay render. In order to achieve clay render, you need to tick override materials in the global switches. This scene has been rendered using the default setting.

Step 3: Increasing the Sky Multiplier

Sky multiplier was set from 1 to 4 in this render to allow more light to penetrate inside the room. Of course adjusting the Fstop value of the camera, or increasing the ISO or decreasing the shutters speed can lighten our scene, but as for now I don't want to touch the camera yet so not to confuse especially the new guys.

Increasing further the multiplier.

4. Adding the Vray rectangular light

If I increased the Sky multiplier or lighten up my camera, I will have a lot of blotches, especially if im using IR Render engine as my primary rendering engine. This is because the distance between samples interpolated would be quiet wide in the dark areas. You can of course increase the samples, but will definitely increase your rendering speed. This was actually one my frustration before.

In order to improve the lighting, we will add a vray rectangular light outside the window. This will help us to increase and improve the lighting inside the interior. In the image above, an additional vray rectangular light has been added. The invisible has been ticked and the multiplier intensity was set to 500.

*tip1* you have to place the rectangular light a certain distance from the wall to avoid burnout of certain walls near the window.

*tip2* save your Light catche, photon map or Ir map and reload them if you are experimenting with light. once you reloaded the saved map, vray will just render your scene.

*tip3* use track mouse while rendering, and point your mouse to the areas you wanted to see first. if you dont like the result, just cancel rendering and adjust those things you wanted to do.

Intensity multiplier @500. I think the exposure is a bit too much. In any case just lower the intensity.

5. Saving the IR and LC passes

IN order to speed up your render during the rendering test, I have a small trick. Saving the IR and LC passes using a fairly small output (e.g. 400px  X 600 px)

*Tip*  Tick calculation phase in both IR and LC calculation so you could see how the calculation is going on. Now you need to stop the rendering process after the IR and LC passes were calculated. In the current map, save the file and place it to any directory you want. Then under "Mod", select "From File and load the previously saved file. You have to do the same with your LC pass. 

*Tip* This only work with the same scene, if you added light, or change the view scene, you need to do the same again.

Another Test 

I lowered the intensity multiplier of the rectangular light to 350 and decreased the noise threshold (QMC Sampler) to lessen the noise. I dont really recommend the lowering of noise threshold when still checking the light as it will slow down the rendering process signinficantly. 

6. Adding Drama

To add more drama, I added the blinds.

But Oh no! what are those noisy stuff on the corner of the wall?
I dont know how the call them in Vray but in this tutorial let me use the word "Blindspot". These areas, are difficult to be reach by both sun and rectangular lights, because when I put the window blind, the light has difficulty in penetrating in those area. As far as I know Vray is a "Biased renderer" and purely work with samples. Blotches is normally cause by lower samples or sometimes the distance between sampling is far causing blotches to the uncalculated samples. (Sorry if I dont know how to explain this clearly, bear with me here. I hope this will become easier to follow  with the next step). 

OK what is the solution then? Increasing the samples, hsph subdivison, reducing the noise? Well any of these things will increase render time, it may help or completely obliterate them, but I bet, your rendering time will be much longer. I ask about this matter on the asgvis forum, but no one responded to me.. Yes no one.
Trying to understand how it works. I spent some time to solve the problem, and this is what I did. after some experimentation and how Vray works at www.spot3d.com.

7. Adding additional Vray rectangular light behind the camera

 
By putting another Invisible Rectangular light (as fill or ambient light) with low multiplier behind the camera, you could actually improve and reach those what I called "blind spots". In the render below, although it is not perfect, but I felt it is a better solution than increasing the samplings.

The above render, I turned off the rectangular light on that window (since its useless now because of the window blind) and created a fairly huge rectangular light behind the camera with multiplier of 2.5. Wow rendering time is much faster than the other image before.