Interior issues 2 - HDRI reflections appearing in mirror

[rkulshrestha]

Hi,

Here is a render and some screenshots. In the first image I am using startup HDR. In the other 2 I am using the 4K2 HDR.  All 3 have Backplate image enabled.
Why does the left mirror reflect the HDR and not the Backplate. In the second and 3rd images below, I rotated the environment HDR and you can see a corresponding change in the reflection.

Cheers
Raj

[LayC42]

This effect shouldn't happen if you use a plane plane outside the window with an emissive material and your backplate image in the color channel.
For detailed infos see attached bip file

hope that helps

[rkulshrestha]

Wow, that was great! I tried to reverse engineer the bip (thanks for that) file.

So it looks like this.

Cheers
Raj

[Will Gibbons]

If your interior is water-tight (meaning all walls, ceilings, floors, windows and doors are all turned on), you shouldn't be able to see any HDRI. I'm confused as to why your mirror wasn't reflecting the rest of the geometry in the scene though.

LayC42 has a good solution. You can move the plane closer to the window/glass and make that plane emissive and use the backplate as the diffuse texture, so you should only need one plane outside of the window. It looks like your screenshot shows two.

[rkulshrestha]

Hi Will

The problem still occurs, see attached BIP.

Raj

[INNEO_MWo]

...
LayC42 has a good solution. You can move the plane closer to the window/glass and make that plane emissive and use the backplate as the diffuse texture, so you should only need one plane outside of the window. It looks like your screenshot shows two.

IMHO the HDRI wouldn't effekt the scene. So the default startup.hdr can be used. If the wall material uses the surface backside mask in the opacity channel, then the hdr pushes more light into the room. (https://www.keyshot.com/forum/index.php?topic=13204.0)


If the extra plane should be an emissive material or an area light is a question of control or render time.

[rkulshrestha]

(I am hoping the two interior Lighting Issues threads will answer a lot of questions for those getting into Interiors the first time.)

So I have 2 more questions:

1. Everytime I apply an IES Light, it points sideways.I have to rotate it by 90 degrees everytime. Happens with all IES lights. I have tried changing the axis in the CAD model and even rotating the light bulb in the CAD model before importing but the IES Light stubbornly refuses to point downwards.

2. I saw Eric's post (https://www.keyshot.com/forum/index.php?topic=13204.0), and cant even begin to figure out how he achieved what he did. Is how the HDR settings were made. Any chance of getting the BIP?

Raj

[rkulshrestha]

An excellent Material Graph Tutorial (https://www.youtube.com/watch?v=5EDJkN6SPLA)

[Will Gibbons]

An excellent Material Graph Tutorial (https://www.youtube.com/watch?v=5EDJkN6SPLA)

I agree. It's a great tutorial, but it doesn't really belong in this thread, and has already been shared elsewhere, in the materials thread I believe.