VR - Images - Reflection and lighting issues

[3dvizual]

Hi.

I am doing this apartment project and I have some issues I dont know how to approach in the right way. (Scene setup) My plan is to both make Stills and VR Tour.

I am using HDRI 1856 from PG Skies in the scene as lighting, which I like very much.

Outside of the apartment is a balcony with a glass railing towards the sea and harbour further away. (I will receive 360 degrees images from a drone later on)

I have been trying to save as a tif file stored with alpha map. But as you can see on the image it does not effect the glass railing.

Also the tree I have on the balcony is blownout and white when I replace background.

I can see The Boundary have made a great VR Tour here: https://www.the-boundary.com/projects/565-broome-soho

Where they have had same situation as I have with balcony glass outside window glass and plants etc. and solved it nicely.

So could anyone tell me how to make this in the right way.?

[maru]

I was trying to wrap my head around this, but with no luck. It should be an easy thing to do, so maybe we are missing something here...

There is this forum post: https://forum.corona-renderer.com/index.php?topic=17065.msg107040#msg107040
But it's still far from perfect, as the reflections and refractions would be affected on all scene objects.

Using background material (corona light mtl or self illumination with rayswitcher) will cause some wrong shading because of light transport issues - https://coronarenderer.freshdesk.com/support/solutions/articles/5000516180-known-bugs-and-limitations

If anyone knows a good solution to this, please share it.

[mferster]

turn off the reflections on your windows, and then render them separately. comp them in when you are in post. whats happening is the white alpha of the tree is picking up the full contribution of your window's reflections when compared to the window. you can solve this later when you get your panorama, and plugging it into the direct visibility override and getting rid of your alpha altogether.

What's with the giant white plane in your scene? is that there for any particular reason?

[mferster]

From the looks of the panorama scene that the boundary made. They made their own hdri/panorama via drone, used that in the direct visibility/reflect/refract overrides and used a sun/sky to light their scene. I could be wrong, but I'm pretty sure they didn't comp the background in post and thus no alpha channel... so that's why it's a non issue

[3dvizual]

Thank you for you answer. The white plane in the scene is not a plane but the glass railing which I have issues with. (as you can see on the alpha). It is not taking this into account.

The last thing you write about making a HDRI/Panorama. So what you think they have done is that they have made there own HDRI with this specific background to solve all of these issues.?

In my case I will not receive a HDRI with a specific background from the site. So I need to combine a HDRI with a panorama in the best possible way.

I will check into your suggestion about window reflections.

[mferster]

it doesn't necessarily need to be an hdri panorama, I think the regular panorama you are going to get will work just fine. for your balcony glass material go to the advanced options and change the alpha mode to always black and see how that looks for you.

[3dvizual]

ok so what you say is that you need to combine a panorama with a corona sun and sky to get the solution or?

Is HDRI combined with a panorama image also in the direct slot not a suitable solution.?

[3dvizual]

I tried changing the railing material to always black. But this means that you can not see the railing glass because it is completely black in the alpha.

[mferster]

in your case, you would use the PGSKIES hdri that you are currently using in your environment slot. Once you get the panorama, you would plug that into Direct Visibility override, reflections override, and refractions override. AT that point you wouldn't even bother with saving your image with an alpha channel.

[3dvizual]

Great thanks. I can see it works fine both with HDRI combined with panorama and with corona sky and map.

But it still does not solves the issue with the glass railing outside balcony. (not visible to the alpha map) This is the one issue I have left now.

I made the glass railing a bit more grey so it is more visible to see.

[3dvizual]

So I guess you just need to go with the sky you see in the render, is that what your saying?

[PROH]

Hi. Just tried to do a quick mockup with a situation like yours (glass + object + glass), and I don't have any problem with the alpha channel. I tried both "thin" and refractive glass, and I tried with both plane and boxes as glass panels, but no combination gives me a result like your alpha render.

So there must be something in you scene, materials or setup, that causes this.

I'm using Corona 1,7 by the way.

[3dvizual]

ok PROH. I will try  tommorow and to go through my scene stepwise and see what seems to be the issue here.

[3dvizual]

I found out the problem PROH.

I had a ocean on a plane behind the railing and therefor the alpha was black instead of grey.

[PROH]

Hi. Glad you found the reason :)

Regards