Author Topic: Bedroom. Need a little help. [Update 21.04.14]  (Read 8589 times)

2013-10-02, 01:38:50

Makovsky

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Hi there!

I have few problems with my project and I hope you guys help me bringing this to an end.
1.First of all, there is strange color shift in my render, all colours and textures are "washed out". I attached pieces of original texture so you can compare it to render. Do I have to edit all of it manually adding color correction or there is something else? I don use gamma 2.2 i have "enable gamma/lut correction" unchcecked.
2. I want the curtain was slightly blurred but with motion blur turned on, the render speed is very low ~1,8M rays/s (average 4-10M). (picture posted are without MB)
3. How to set best materials for lamp shade and curtain? I try with refraction and low glossines but Im not happy with the result.
4. Overall shadows are preatty weak, its missing good constrast contact shadows. Can you help me with the settings?
5. I want to do a carpet using corona scatter. Is it good idea? Can you post links to some kind of tutorial how to do that?
6. And last but not least, will you change something in this scene? I plan to add bedding and carpet later, but maybe you have some suggestion to current view?

Thank you in advance. :)
« Last Edit: 2014-04-21, 18:55:50 by Makovsky »

2013-10-02, 08:15:26
Reply #1

Ludvik Koutny

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1, Corona does not support non-linear workflow, so you need to work in linear color space...

2, Motion blur will always have some overhead. Only workaround i can think of at the moment is rendering motionblurred curtain on the black BG and compositing it in, or doing the blur in post, or just waiting longer.
3, That's what translucency is for.
4, You do not anyhow tweak contact shadows. Corona is a path tracer, that means it simulates how light behaves in real world. If you take a look at the photos, they do not look like like full of ambient occlusion. Light reflects, AO is just a very simple trick that does not take light bouncing into account. That being said, you can render out AO pass if you want, using Texmap render element.
5, There are better ways, like hair&fur or grass-o-matic plugin.
6, I suggest first using LWF to see how your scene looks with correct texture gamma, and then re-evaluate scene and go further.

2013-10-02, 10:18:15
Reply #2

Makovsky

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I read about linear worlflow, but i've never been convinced to use it. You posted screen image with output gamma 2,2 , shoudln't be 1.0? Isn't this an essence of linear workflow, to force textures and colours to work in 1.0 colorspace?

2013-10-02, 10:28:56
Reply #3

Ludvik Koutny

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I read about linear worlflow, but i've never been convinced to use it. You posted screen image with output gamma 2,2 , shoudln't be 1.0? Isn't this an essence of linear workflow, to force textures and colours to work in 1.0 colorspace?

No, output gamma affects output. You have it set to 2.2 if you use regular formats, and 1.0 if you use EXR workflow. I assumed that someone who does not use LWF also does not use EXR workflow as well, thats what i posted this one.

What affects textures is Input gamma, and that is correctly set to 2.2 on my picture, so 3ds Max assumes that bitmap textures already are gamma corrected, so they do not need to be corrected again. It also means that if you ever use any EXR or HDR bitmap, you will have to manually override gamma to 1.0 in bitmap loading dialog, because linear HDR formats like HDR or EXR do nothave gamma baked in them. A lot of people does mistake of opening for example HDR images with wrong gamma, and then reverse-correcting them with something like VrayHDRI. Which is of course wrong workflow.

You will mostly be opening gamma corrected textures as that is majority of them, so you want to have input gamma set to 2.2, as it is on the picture.

If you have Max 2014, this is being taken care of automatically, as Max 2014 has new intelligent input/output gamma solution based on individual formats. If you have Max 2014, then also make sure you have latest Service Pack 3 installed.

2013-10-02, 10:41:07
Reply #4

Ondra

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saying you are not convinced to use linear workflow is like saying you are not convinced that 1+1=2. Sure, use gamma to tweak the image in postproduction, but the baseline from which you start should be gamma 2.2 LWF image.
Rendering is magic.
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2013-10-02, 10:51:35
Reply #5

Makovsky

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I said I'm not convinced because I do not understand entirely how it works ;) and for years I was using non LFW in vray/indigo with satisfactory results. (so why I should change it) But maybe i should read about it a little bit more.

So for now, to use LWF do I have to reset all materials and start from scratch? Or just enable it and start render?

2013-10-02, 10:56:53
Reply #6

Ludvik Koutny

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I said I'm not convinced because I do not understand entirely how it works ;) and for years I was using non LFW in vray/indigo with satisfactory results. (so why I should change it) But maybe i should read about it a little bit more.

So for now, to use LWF do I have to reset all materials and start from scratch? Or just enable it and start render?

Just enable it, that's all...  if you set it according to the picture, and assuming you do not save your images in EXR format, then that is all you need to do... On the picture you posted, you are already using LWF, as Corona uses LWF by default...  but 3ds Max does not know about it, so it is gamma correcting textures twice. By enabling the settings according to picture, you will basically just make 3ds Max handle textures correctly for LWF.

2013-10-02, 11:17:24
Reply #7

Ondra

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so why I should change it

Have you ever in the last two years produced a visualization that could be told apart from a photo? If yes, then you still have a room to improve ;)
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2013-10-02, 12:31:06
Reply #8

Alessandro

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My 2 cents:
your are using a crazy value for highlight compression, 500, that's one of the reason why you've got low contrast, maybe you could try to work with a more realistic camera exposure.
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2013-10-02, 14:58:36
Reply #9

Juraj

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My 2 cents:
your are using a crazy value for highlight compression, 500, that's one of the reason why you've got low contrast, maybe you could try to work with a more realistic camera exposure.

For some reason I thought 99 was highest :- ) But I find 5-8 to be already quite extreme (very dull) and only use when absolutely necessary.

I find it hard to believe you worked non-lineary inside Indigo, is that even possible ? I though it would be prepared by default loading all textures as sRGB and 2.2 having internally.

But like anyone said, LWF should be no-brainer. It's still science to get something realistic, so having one less problem because is gamma is good check-off.
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2013-10-03, 00:56:39
Reply #10

michaltimko

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I find it hard to believe you worked non-lineary inside Indigo, is that even possible ?


For me, it was more comfortable than working in LWF, dunno why. But i had completely different workflow in indigo and it was working quite well.
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2014-04-21, 18:55:17
Reply #11

Makovsky

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Hi, its been a long time since my first post but only recently I found time to bring this scene to the end. Its not perfect yet. I want you guys to tell me what would you change here / improve / add / remove etc., all that comes to your mind. Especially how to make realistic curtain material with corona and how to tweak settings to get the best results with PT+HD mode. Thank you in advance :)

2014-04-22, 12:21:41
Reply #12

ivanziva

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I have two questions ( probably stupid )

1. Does VrayHDRI import HDR images as 1.0 by default, and if it's not a case, how to override it?
2. And if one  import HDRI (e.g. MAX environment slot) as an bitmap image, how to rotate it?

thanks, and don't remind my ignorance :-D

2014-04-23, 12:53:37
Reply #13

ivanziva

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2014-04-23, 14:10:59
Reply #14

klipanos

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If you need suggestions about decorating the room we are going to need informations kind of where is it, is it hotel???, budget and other stuff...