The light balance in rendering | Cg Blog

The light balance in rendering

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When I work on a rendering I apply a personal workflow. It’s nothing secret or special, but it’s helpful to me and for every person who was in my trainings. I usually have 4 steps. They help me to keep track control the evolution of the work:

  1. Balance of Lights (with default material)
  2. Exposure correction (after the application of texture)
  3. Adding reflections (Glossy and not glossy)
  4. Final rendering setup

I figure out these 4 steps as a hill to climb:

A very hard start, a point of verification, and finally an easier way down.
The start is brief, artistic and complex. The conclusion is longer, technical and easier.

The 1st step it’s “only” about putting lights in the scene. You have to decide the primary light and consequently add the secondary lights, fill lights and so on. I usually use the V-Ray default material  (equivalent to Kodak 18% gray).

This is – from a technical point of view – the easiest step. There are few parameters to control, but it is artistically the most complex step. This step is really hard for the people who are very good with the only parameters! Yes, because the “parameter control” is not the main topic at this step. The most important topic is the way the lights are related to each other: Light Balance. Artistical people are advantaged.

A great light balance make the image “more” 3D! It creates volumes and depth in the image. A bad light balance make everything flat.

The light balance is the foundation of the image, if the foundation is not strong the building is always in danger. But if the foundation is great you can add materials, backgrounds, lights, you can play with the parameters: the result will be always fine.

Here my advice: make sure that the light balance works fine before proceeding. Try also the second step (adding textures), sometimes the colors help the contrast, but never go over if the image does not work! In my experience as trainer I know the problems in 90%  is in the beginning: light balance.

Everyone knows: good morning starts in the morning.

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Check the videotutorial, donwload a sample scene a repeat the exercise.
Learn how to model a scene using the lights.




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EXAMPLE: from Francesco Romanucci (student) – Light balance is OK! – ( click to magnify )


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In the following Final render, Francesco just added materials: lighting is the same – ( click to magnify )

CONCLUDING

As you can see, the illumination in the two images has the same distribution. After complete the light balance, just add the materials and the render is finished in brief! My students knows that the shading is not so complicated: 1 day leargning. That is not the problem: The crucial point is the light balance.

No parameters can help you, just your imagination.


36 Responses

  1. This is very insightful – thanks

  2. saeid says:

    hi, ciro
    thanks

  3. sachin walvekar says:

    One of the smallest tutorial that can make the largest impact on rendering quality. Simply great. Thanks a ton for the tutorial.

  4. wai phyo says:

    hi,
    this is nice tutorial.If you have time,pls share using of vray sphere and vray plain light in interior design!
    More over their useage,disadv&adv..etc..thk 😉

  5. Timty says:

    Thanks great secret… Hope to see more.

  6. elok sitoresmi says:

    waaaaaaaaaaaaaaaaaaaaaa…. cOOL..!!!!!!!!!!!!!!!!!!

  7. inner says:

    hi
    thanks

  8. piyush joshi says:

    i love ur tips…thanks a lot..!

  9. araojadhav says:

    thanks friend for your copration

  10. muneer says:

    path to success

  11. bob says:

    thk U Broo,

  12. vandatnguyen2004 says:

    hi thanks

  13. 3D Architectural Renderings says:

    I always enjoy your posts. Keep them coming!

  14. Wonderful, these are great tips. I’ve just started sculpting in 3D and have become addicted. I’ll be following your posts from now on.

    My first sculpture is now on my blog, I chose to try and model the character of J F Sebastian from the film Bladerunner. Environments and machinery are next on my to do list.

  15. eric noviyanto says:

    nice pic

  16. Yanto says:

    I like it,tanks

  17. NADEEM says:

    this is good tutorial but i want full tutorial of v ray

  18. Sean Shim says:

    Hey Ciro!
    Thanks very much for this, especially the diagram. Super helpful.
    I see that you also do an exterior lighting setup using Guthrie’s HDRI/exr files – if you have time, a tutorial dealing with mixing the two together would be really appreciated!

    I have a lot of trouble balancing an interior lighting scheme that has exterior light (guthrie hdri’s) spilling in through large windows.

    best!

  19. designer says:

    very nice tnx

  20. holake says:

    how was the rendering setup?

  21. stuwy says:

    hi ciro
    i just want to thank you for spending time in writing your tutorials! i just get it! i have always been apprehensive about learning the ropes properly to develop a nice quality render, and with your help I hope I hope to become more courageous and adventurous.
    hope you’ll have an english running workshop in europe soon! thank you!

  22. swarthykhan says:

    Thanks Ciro,
    That was really helpful.
    However there is one thing that I quite don’t understand. In vray manual for radiant power it says that 100w light bulb only produces 2 or 3 watts of visible light and we shouldn’t make a mistake about it but in this tutorial your student used 80w planes. Could you elaborate?
    When I use these settings I get nice results for planes but not for the ies lights. Is there something that I miss? By the way I used vray sun in the scene. I believe I make mistakes with the intensities of the lights because I can never achieve a good light balance.

    • Ciro Sannino - Auth says:

      Hi swarthykhan,
      first of all it’s all about balacing, not watts. It means that 2 lights could be 5 and 10 watts OR 3000 and 6000 watts that’s the same in terms of balance. Definitely the same.
      About IES the measure units in ‘power’ option is “candles”, for this reason you need to start 120000-150000.

      But the most important thing is balancing you “see”, not the measure units. Using correctly te watts can help you, but that’s not the point.

  23. swarthykhan says:

    Thank you for your kind, informative and swift answer, Ciro.
    Most people on the tutorials emphasize the importance of world units and I get that and may be that is the reason I deviate from the main point. This is 3d after all. We are allowed to do anything and nobody cares how we do it as long as the output is fine.

  24. Romit says:

    hi ciro,

    thank you very much for this wonderful tip about lighting. Please post tutorials regarding interior lighting in vray incl rendering, it will help me to understand interior lighting much better.

  25. dalia says:

    its amazing we waiting it to be downloadable

  26. rooha says:

    hi!
    very good!

  27. vikoum says:

    hello ciro,

    I saw your reply to swarthykhan and you said that the measure units in power for IES is in candles.

    Well…when I us some IES lights from lighting companies which provide its IES lights through their sites, I notic that when I insert an IES light and go to the parth of the IES in order to indicate it, automatically the power units field is filled with its value, for example 7500. I also noticed that this number, most of the times is the lumens value of the light.
    Have you ever notice something like this, or is it something I did not understand it in the wright way?

    • Ciro Sannino - Auth says:

      Hi VIKOUM,
      I underline is in candles becasue many people say me “ohh woooo 7500 is it too much?!” – So I just say don’t care the number, just increase it until you have the light you want. This will not break photorealistic rules. (the most important thing!!)

  28. Frederyco Martins says:

    Hi Ciro, how´re doing? Great tutorials, thanks for sharing.

    I found a little confuse that you made the fill light behind the sofa simulate the tv, am I right or I misunderstood it? What do you think of putting a vray light in front of tv to do the job, would it be a silly solution?

    Cheers.

    • Ciro Sannino - Auth says:

      Hi Frederyco,
      the fill light behind the sofa “could” be a tv… but also fire or whatever you want, since it’s not in the shot. In case your tv is IN the shot I hardly suggest to use VrayLightMtl, with a tv screenshot as texture. It works perfectly.

  29. fixcode84 says:

    Thanks for this tutorials!

  30. amin naderi says:

    just amazing man tnx

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