Reflections

[glorybound]

I have been gripping about this for years. I have trees behind the camera and an HDRI with trees and clouds. However, nothing reflects. It is used to reflect pre-IDK V-Ray NEXT. I use RawTotalLighting to boost it, but do I have to? What has changed? Is there a reflection distance limiter or something I don't know about?

[Joelaff]

Part of why you are seeing little reflection there is the fresnel reflection laws, which cause reflections to be pretty much zero with looking flat on top a plane.

You could disable fresnel reflection. Increase the IOR, or use a Falloff map and set the minimum reflection manually with it.

If there are objects that are not reflecting that should be then would have to see a scene.

[glorybound]

You see the grass and bushes, but you see nothing past that. Below is what I would expect to see in glass reflection.

[Joelaff]

Would have to see a scene. Weird, though.

Increase max reflection/ refraction depth?

[glorybound]

Would have to see a scene. Weird, though.

Increase max reflection/ refraction depth?

Yeah, I believe I have tried that. It used to work just fine pre-Next. I know they separated the specular and reflection or something. Something changed; I remember that.

[Joelaff]

Oh, it’s your hdri in the light you can’t see? What if you set Diffuse amount of the dome light to 0.1 and the overall strength x10 (or a factor of 100 each way, etc until you see it).

Or make two dome lights, one for reflections.

[^Lele^]

Yeah, I believe I have tried that. It used to work just fine pre-Next. I know they separated the specular and reflection or something. Something changed; I remember that.

Specular and reflection are one and the same now, yes.
But that wouldn't account for the failure to reflect anything behind camera.
I'd need a file to be sure of what your problem is, it works for me in naive tests.

[fixeighted]

You just need to unlock the reflection fresnel and nudge it up to an amount that gives the desired result.
Roughly 3.0 seems to be about right.
The tooltip states (when locked) it's based on the refraction ior, which, whether it's deemed to be 'physically correct' it is clearly not

[seandunderdale]

If there is literally nothing, at any exposure, then Id say there something technical going wrong. Something a tickbox here or there would fix...but if it is there, Id say its purely exposure.

Look at the sky in your reference photo...its massively blown out, and the dark wood looks really reflective. The window glass in that photo looks like chrome. I wouldnt change real world fresnel values, unless the shot is locked and the client wants a final change. Then Id do a render override and crank out a quick pass for it. But as a rule, Id try to compensate for things as they are in the real world. ie. that photo looks like it is "exposed for the dark areas" in that shot.

[piotrus3333]

You see the grass and bushes, but you see nothing past that. Below is what I would expect to see in glass reflection.

this is Photoshop or reflective coating on glass...

[piotrus3333]

and those coatings are usually metal based:

[fixeighted]

Just as an experiment, if you search 'house photo' then the vast majority of results show clear reflections in almost every similar scenario.
They are a little darker as expected but not as dark as a default glass shader would give.

I'll suggest that some houses have dirty windows, some have coated glass (yes the garage door look like reflective mirror glass tbh), etc. etc.
In the majority of the images I viewed you can clearly differentiate between the obvious reflections and what is within the rooms, where the angle and lighting permits.

The solution is to disregard the linked ior and use one which represents what you perceive to be correct

[seandunderdale]

Id also be sure to have double sided / reflect on backside reflections ticked on...and double sided / glass with thickness. Makes a big difference in my automotive work when Im using glass shaders.

[piotrus3333]

Just as an experiment, if you search 'house photo' then the vast majority of results show clear reflections in almost every similar scenario.
They are a little darker as expected but not as dark as a default glass shader would give.

I'll suggest that some houses have dirty windows, some have coated glass (yes the garage door look like reflective mirror glass tbh), etc. etc.
In the majority of the images I viewed you can clearly differentiate between the obvious reflections and what is within the rooms, where the angle and lighting permits.

The solution is to disregard the linked ior and use one which represents what you perceive to be correct

this search will give you heavily processed photographs property market is known for.
if you are looking for some form of reality regarding reflections in glass go for "street photography":
Wallpaper : 35MM, candid, Europe, issues, London, photo, photography, reflection, reflections, Sony, sonya7, sonyfe35mm, street, thinking, unitedkingdom, window, woman, portfolio, onsale, faceless, streetphotography, England 2048x1365 - - 665456 - HD Wallpapers - WallHere

[fixeighted]

I really just looked for anything that looked like regular 'snaps' that were odd angles and not processed in any noticeable way.

Besides that, I looked at the issue in a way that gave the result I thought Bobby was after, with the least amount of effort, which is that one value raised by a little.
After all, I thought that what we're essentially doing is using virtual tricks in the same way as pro photographers use tricks to balance and present the best image, so whatever works in my book