Author Topic: How to boost reflections?  (Read 348 times)

2020-04-10, 12:28:29

patrick.testa

  • Active Users
  • **
  • Posts: 56
    • View Profile
Hello everybody,
my problem is the following: I need to render some interiors with wallcovers and textiles that have  metallic effects, silk and other materials with particular reflections, like in the example images.
I make good looking materials in a testing scene but in the rooms that I have to render, there is very little exterior hard light (if at all...) and the illumination is mostly diffuse, with recessed led strips and a few small cone spots, so the reflections don't come out very much, even if I exagerate them.
My workaround is to render a reflection render element and add it in Photoshop where I need it, but I'd like to know if anybody has a way to do the same thing directly in 3dsMax with some material that can add reflections on top of the base material to boost them even if it's not physically correct. If I remember well, there was something like that in Vray…
Thanks for any suggestion!
Best regards,

Patrick

2020-04-10, 13:25:57
Reply #1

Juraj

  • Active Users
  • **
  • Posts: 4079
    • View Profile
    • studio website
If you are satisfied with your material, it's only matter of light & post-production. But I would focus on the light.

You don't need to change the global light of the scene. In advertising, a reflector light can be placed to shine on main product and than masked away, or you can place reflector in way that it affects the whole scene.
The sharper the light source, the stronger the glossy effect (and vice versa, large soft lights provide diffuse reflections).

(Vray has a fake option, but it's inverse to what you want. VrayLight has option to reduce specular contribution, effect that can be achieved in Corona with invisible plane mapped with reduced refraction in ReflectionOverride MTL, effectively creating a polarization effect sort of like in photography)
talcikdemovicova.com  Website and blog
be.net/jurajtalcik   Our studio Behance portfolio
Instagram   Our studio Instagram, managed by Veronika

2020-04-10, 14:22:42
Reply #2

agentdark45

  • Active Users
  • **
  • Posts: 535
    • View Profile
This may seem obvious but have you tried cranking the IOR of your material to something >5. For reflective silk materials as you've posted I've had great success by placing a heavily contrasted version of the main texture map in the IOR slot (inverted) or the reflection slot along with various maps in the anistropy + rotation slot. Tinting the reflection colour (either using a map or solid colour) can also work depending on the material. This coupled with the usual falloff-diffuse tricks can produce some very convincing materials, couple of examples attached.

My materials are quite evenly reflective, whereas for your material you would definitely need to add a map to differentiate the reflective parts from the diffuse.

« Last Edit: 2020-04-10, 14:27:47 by agentdark45 »
Vray who?

2020-04-10, 15:46:59
Reply #3

patrick.testa

  • Active Users
  • **
  • Posts: 56
    • View Profile
Thank you both for your answers!
Yes, I've already increased IOR, maybe even too much; the problem is in the lighting, as my client wants evening light, soft illumination, strong reflections and no overexposed areas all in the same image… no comment!
I'll try adding hidden illuminating planes; I just hope that if won't mess the scene because I render different cameras from the same scene and those tricks sometimes work from an angle but look awful from another… I know I should place different reflectors for the various cameras and turn them on and off but I never have time to refine things as much as I would like because of short production times…
Thanks again!

2020-04-10, 16:24:12
Reply #4

TomG

  • Corona Team
  • Active Users
  • ****
  • Posts: 3186
    • View Profile
In case it helps, don't forget that the Corona Camera has an Include/Exclude list, so you could make it so particular reflectors are only visible from particular cameras, and then you don't need to remember to turn them on and off as you render one view and another.

2020-04-10, 16:39:11
Reply #5

patrick.testa

  • Active Users
  • **
  • Posts: 56
    • View Profile
Yep! Thanks...