Rendering with Reality

Toyen

Hey there everyone! Just got Reality (loving it!) and after some playing and testing, I decided to give it a decent render.

I am reading through the manual (very well written!) but I thought that I´d ask for some tips and tricks from other Reality users.

So here are the scene details:

This is the picture after 2 Hours of rendering, at 589 samples and 130% efficiency.

The render mode is Hybrid with one of my GPUs helping.

As you can see it is nowhere near finished as there still a lot of artifacts in the scene.

The resolution is 1280x700.

Scene setup:

I am using Reality´s sun light at a morning angle.

I am also using IBL with the image of manhattan you can see through the windows.

The image behind the windows however, is not the IBL, it is a plane that I placed there with the image on it.

The room is a closed box (has all 4 walls, floor and ceiling) and there is no light source inside so the only way the light from outside can get in is through the windows.

Which is now making me think, could the plane with the image be blocking the IBL and sun lights? If so what would be the solution if I want the background behind the windows be the view of manhattan and neither Daz Studios enviroment nor IBL looks as good as a simple plane with the texture on it?

Everything that is not in the camera view in the scene is hidden.

Please let me know what you think : )

Toyen

Here´s the render after 4 hours at 1000 samples. The quality is almost the same. I think I must be doing something wrong.

SimonJM

I suspect you have over-lit the scene which is not helping. Is there a Sky as well as a Sun in the Lights? If so, especially since using an HDRI as well, I'd be inclined to turn off the sky.

Toyen

I might give it a try. I didn´t think this could be the problem because the scene is pretty dark. The image applied to the IBL is not an HDR though, just a regular image so I added the sun light to make sure there is enough light in the scene.

Toyen

Okay here´s an update:

I rendered the shot 5 times with different settings and at 100 samples I stopped to see the difference.

1. IBL+Sun and sky lights. The plane with Manhattan picture is still there possibly blocking the light.

2. IBL only. Manhattan plane still there.

3. IBL only with the plane gone. You can see huge improvement when it comes to the nosiness so I guess that plane in front of the window was indeed causing some issues. However, the manhattan picture applied to the IBL sphere does not look good at all.

4. Sun and Sky light only. Same as picture 3, you can see the noise improvement if you compare it to the first 2 pictures. However, pure blue sky is not what I want. So how do I get the texture there?

5. Here i have one mesh light placed outside the window shining inside with the sun preset and the Manhattan plane is also placed behind the window again.

Disadvantages: the light is shining inside not towards the place behind it so you cannot see it. Plus, there is a reflection of the plane that´s emitting the light in the window glass which should not be there if I want to make it look like the light is natural and coming from the sun.

But again, the quality of this image is much better than of the first 2.

Toyen

And here are two more renders.

First one is an outdoor scene where the only light is an IBL and this picture has 500 samples yet the quality is still quite horrible.

And the second one is a very simple studio scene with two mesh lights and at only 130 samples (with rendering efficiency of 1100) it looks like a rather decent image.

Any feedback would be much appreciated! : )

SimonJM

I have found that 'decent' HDRIs provide both good, and efficient, lighting in LuxRender. The main issue not really knowing until you start the render of how the light and backdrop are going to look.
The exterior image may well 'pick up' as 500 samples is not really enough in this instance. What is enough will vary from render to render: I have what I consider to be quite a good image quality at 200 samples, but that was a very simple setup with minimal everything (lights, geometry, etc.) and I have had renders that go to 3,000 samples and could still do with a few more. A long time ago Paolo (Pret-a-3D) gave a rule of thumb that 2,000 samples was a good value to aim for.
I managed to miss you mentioning the fact that the background was a plane - yes, that'd be partly the issue as it would be blocking light. Unless you can get an HDRI of the skyline you want I am not sure what to suggest, beyond post-working it in,