stuck in progress

[dechrigi]

Hi everyone

I really got into indigo recently and i am trying to get my first complete scene together, but recently i got to the point where i feel the renderings still look somewhat fake, but i don't have a simple explanation of what I'm missing... the closeups seem to work better, but the overview images just don't look right somehow - I know from other fields that after a working on the same project for a while, one tends to forget about the most trivial bits So comments, criticism or hints on possible improvement would be highly appreciated!

p.s.: I using blender 2.49 as modeling tool and indigo 2.2.12 for rendering. By the way, the exterior a hdri map and not rendered.

[Soup]

The depth of field suggests something weird about the scale of the object - its blurred in the foreground, and in the background, as if it's too small. Either have the focus a little further back, in the middle of the shelf, or have no foreground blurring
Maybe adjust the composition too so that an object becomes the focal point, rather than the top edge of the shelf.

Maybe some objects scattered about in the background, to give a feeling of a lived-in space - dosen't need to be anything detailed, or in focus, but just something no arranged so neatly

See if that helps :]

[dechrigi]

Thanks for the advise soup! I used blendigo to export the scene, so it might be that I messed up with the blender-unit/meters ratio... I'll check that. Also I'm thinking about adding a plant or something in the background - but that will probably take some time to create

By the way, soup's comment refers to the the close up of the book shelf, because I forgot to upload the other images in the initial post (and then had to wait until the post was accepted until I could add the other ones...) silly me

[galinette]

Your images are not totally noise-free, and the noise generated by Indigo often looks non-natural. Maybe a longer render would look better.

The white walls are maybe too uniform, and too white (which makes the corners not dark enough). Decreasing the albedo of the walls, and applying some subtle maps to make them less uniform, would help too.

Etienne

[Silmä]

What kind of lightning setup you have? Right now the room is almost completely uniformly lit, and the foreground (black table and sofa) doesn't have depth in it.

Block the light source behind the camera, and the result will be a lot more dramatic. When there's a huge light source visible in the picture, one naturally expects it to be the prominent one.

And amazing detail in the window!

[galinette]

I would bet there is no other light than the outside envmap... But the white paint has a too high albedo and uniformizes the light.

On the window frame detail, I think the glass is lacking some absorption. Try this one : http://www.indigorenderer.com/materials/materials/250 , it was made with real glass spectral data (I'm working in glass R&D!)

Etienne

[CTZn]

I like the windows work very much too. Your scenes have a good potential, I'm looking forward for the lighting tweaks. You could use layers for the matter, did you ?

[Silmä]

I would bet there is no other light than the outside envmap... But the white paint has a too high albedo and uniformizes the light.

I'm guessing there's another set of huge windows behind the camera. The clay render is also totally uniformly lit, and i don't think the clay material is 100% white.

If there's another set of windows, the alternative way to handle the lightning (instead of blocking the windows behind) is to change the envmap to a more sunny one. That way there would be a lot more light in the other end of the room, and more depth.

[dechrigi]

Thank you for your comments! I'm just rendering some of the shots again right now, this time with longer render-time, in order to get rid of the noise. I'll post the results as soon as possible.

@Galinettte: Your right, I really only use the hdri env map of the exterior to lighten this scene - Concerning the walls, they already have a small scale bump map (stucco, slightly visible in the book shelf rendering) and a larger scale bump map (to make the surface uneven), but as you correctly noticed the albedo is a uniform, pure white. This is definitly something I will try to correct with a new texture of some kind. Maybe your right, and this could also give the whole lighting of the scene a new degree of realism, so thanks a lot for this observation! P.s.: The sodalime glass material looks great, I'll give it a try!

@CTZn: Thanks a lot! The scene is a currently just rendered with default options concerning lightning, tonemapping, etc., but I will now try to get into the different possible lighting tweak methods that indigo offers. At the moment I'm not using any layers. Would there be some kind of possible benefit in using layers, having only one light source (=env map)?

@Slimä: Thank you slimä! Actually, there is no light source behind the camera, and it's pretty much just all walls, but of course the big window front visible in the rendering lets a lot of light in already, that probalby reflect from the high-albedo walls, as mentioned above. I really like the idea with the sunny environment map, I'll try this out - only problem is I'll have to wait until we have some nice weather here on a weekend

So thanks again to you all & cheers!

[CTZn]

Would there be some kind of possible benefit in using layers, having only one light source (=env map)?

No, obviously

So the issue with the dull lighting might be the low (or compressed) dynamic of the environment map, that tree outside is looking wrong in the colored scenery. If you have access to the environment texture settings you may want to lower its offset and in turn augment the gain (lower env texture C parameter and boost its B parameter), or edit the picture dynamics in a dedicated application (Picturenaut as suggested recently). But the first option is a good take. By doing so you should increase the contrast of the environment, and as a consequence it will introduce a more caracterized lighting in your scene*. Even shadows may result better defined.

Using the Indigo sunsky will most probably address the dynamic range of the render at once; then, render an alpha version wich will allow you to composite any LDR background you like against the render**.

Oh, now that you are in the lighting process I recommend that you use the linear tonemapping (camera tm is for final ). Because the default (Reinhard) tonemapping is adaptative it is a poor marker of the absolut light powers in the scene, likely to cripple your own evaluation (in my opinion).

I hope that helps or makes sense at all.

* lowering the lowest level and increasing the maximum one is litterally stretching the dynamic range.
** see the "appartment with terrace" from dcm in the finished works forum, he just posted a hint on this

[dechrigi]

@All: Finally I found the time to implement some of the suggestions mentioned in the posts above. The most important things was that I turned down the albedo of the walls by about 5% and changed the gain of the hdri env map - that made a huge difference alone! There are some better defined shadows now, which I think enhances the realism quite a bit.

Also, I increased the B parameter for small- and large scale bump map on the wall material, trying to make them look less uniform. Additionally I added specular (dirt) maps to some of the wooden materials and replaced the glass material as suggested.

Finally I took more time to render the results (I also helps that I'm now owning a new computer with a i7-870 cpu, which speeds up the calculation by amazing 600% (weeeee !!!) in comparison to my old one (athlon 64 dual core 3800+) !

@CTZn: Thanks for suggestions! The possibly low dynamic of the hdri env map is interesting point which I haven't thought of until now... I made the map myself from multiple camera shots using PTGui, and never actually checked the histogram of the result. For the moment I just tried turning up the gain, but I'll take better look at this soon (or possible redo the whole thing from scratch).
The map is pretty low-res and has some ugly stitching errors anyway so I'm also considering using the method you described in your post (render an alpha version & do composite with LDR background). The only problem I'm facing there is that I'm using a transparent material (with some dust on it) for the windows and therefore appear solid in the alpha render ...or am I doing something wrong here (is there a way to make the alpha render take into account material transparency?) Concerning this, I haven't be able to spot a hint (about alpha rendering & composite) in the "appartment with terrace" thread, or is it possibly another, similar thread?
P.s: I tried the the using the linear tone mapping instead of reinhard in the latest renders, which I think also improved the renders.

[dechrigi]

p.s: and for all of you 3D geeks out there - a anaglyph (3d red-green goggles) version

[zeitmeister]

This is getting very nice!
Fill your scene with small props like glasses, paintings, electronica...

I am very excited!

[CTZn]

Great news dechrigi, thank you for the feedback. Mostly I've been reporting hints that I learned myself from others but still, I do have an ego

The only problem I'm facing there is that I'm using a transparent material (with some dust on it) for the windows and therefore appear solid in the alpha render ...or am I doing something wrong here (is there a way to make the alpha render take into account material transparency?)

Some say there is a way and call it a bug, so you are on your own as far as I am concerned. Theorically you are supposed to use diffuse materials only to ensure opacity for the alpha, so just give a try to other materials in case you can exploit that said bug. I didn't dig in that direction, but yes, support for transparent (and parametrized) alphas is an active user request wich should happen at some point.

Great progresses indeed.

[galinette]

The most important things was that I turned down the albedo of the walls by about 5% and changed the gain of the hdri env map.

What is your albedo now? Generally, you should not set it above 80%. Even white paint has an albedo which is far from 100%. Only very technical materials have high albedos (such as spectralon, with an albedo around 99% on a spectrum wider than visible...)

To high albedos on white rooms have two main effects : they wash out the shadows completely, and cause rendertimes to explode (as the rays can bounce many time and still have an important contribution to the lighting)

Nice improvements, though. The image looks under-exposed now, because the windows are much more bright than the room. You could:
- Increase tonemapping gain or exposure. This would expose the room correctly and overexpose the windows.
- If you want both exposed correctly, you need to use HDR tonemapping techniques. Export to EXR image and use an HDR tonemapper (such as photoshop "convert to 8bit", PTGui, or luminance HDR)

Etienne

Etienne