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fabian4d
08-16-2016, 05:50 PM
Hi

I have problem with the shadow as it has no definition, it can be?

Thanks134065

jeric_synergy
08-16-2016, 07:00 PM
What exactly do you feel it is lacking?

fabian4d
08-16-2016, 07:15 PM
I think the shadow is very weak , as missing oclussion. It appears to be floating

Snosrap
08-16-2016, 09:08 PM
Add an Ambient Occlusion node to the diffuse channel of the wall and ceiling joists. Light naturally has trouble getting into nooks and crannies, an Occlusion node can make that happen.

jeric_synergy
08-16-2016, 10:57 PM
Add an Ambient Occlusion node to the diffuse channel of the wall and ceiling joists. Light naturally has trouble getting into nooks and crannies, an Occlusion node can make that happen.
What's the render hit on that like?

Surrealist.
08-17-2016, 01:16 AM
From the look of you scene it seems like you have a Point Light in the middle of the room or even an Area light used as a fill light. That will have a tendency cancel the effect of shadows on the surface.

The second contributing factor is the size and position of your Area Light above the ceiling. It is too small and too close to cast soft shadows. When you have hard shadows and another light affecting the surface you will get what you have there. additionally if you move back and size up the fill light (assuming it is Area too) and turn on shadows you can cast soft shadows on the interior as well.

Ambient Occlusion as mentioned will also help. But it is really a fake for something that happens with Global illumination with out as much of a hit on render time.

For a scene like this you could do a few things to help it look better all around:

1) Area lights large enough and far away enough to cast soft shadows
2) Additionally use Global illumination with some kind of environment in the background such as Image World
3) And don't forget to use a linear workflow so you are not trying to over-light the scene.

For architectural renders these basic tips will help.

Here is a similar scene with only Area Lights.

Set up light so:

http://forums.newtek.com/attachment.php?attachmentid=134076&d=1471418013


And the render:

http://forums.newtek.com/attachment.php?attachmentid=134074&d=1471417598

And the same scene with GI and Textured Environment:

http://forums.newtek.com/attachment.php?attachmentid=134075&d=1471417608

Snosrap
08-17-2016, 08:29 AM
What's the render hit on that like?

Negligible. And it's surface specific and not necessarily global.

Surrealist setup a great scene, but ambient occlusion is different than shadows so the image still suffers at the contact points. Other than using a radiosity method, ambient occlusion is probably the way to go. Attached is an example of a portion of a rendering I recently did with and without ambient occlusion. It's very subtle but makes a world of difference and I used Final Gather global illumination in both.

134082
134083

ActionBob
08-17-2016, 12:19 PM
Shadows problem? Get the Vorlons to deal with them... But then you have that whole mess to deal with...... ;-)

-Adrian

Surrealist.
08-17-2016, 11:01 PM
Negligible. And it's surface specific and not necessarily global.

Surrealist setup a great scene, but ambient occlusion is different than shadows so the image still suffers at the contact points.


Actually the scene does not suffer contact points at all. If you look closely they are there. What it suffers is true GI bounced light or a fake occlusion method. The second image introduces GI which smooths out the scene with more bounces of light. But the contact points are the same relatively in each scene. The GI does enhance the contact points significantly though in a more smooth and natural way.

But in either case you have to make sure you are not adding too much light.

Here are some samples which may point to reasons why you might have to add AO to get more contact points using GI.

Here is what you get with one area light sized up and at a distance to get soft shadows:


http://forums.newtek.com/attachment.php?attachmentid=134096&d=1471494371


Here is Radisity With only Area lights and shadows on. (no environment light)

http://forums.newtek.com/attachment.php?attachmentid=134097&d=1471494504

Here is the same set up with shadows off on 2 Area Lights on on each side. Notice how the Radiosity starts to loose its effect.

http://forums.newtek.com/attachment.php?attachmentid=134098&d=1471494672

Now here is Radiosity with Image Wold on:

http://forums.newtek.com/attachment.php?attachmentid=134099&d=1471494903

Notice how similar that is to one Area Light in the first example. It is mainly missing the nice even bounced light from GI

And now Radiosity and image world, 2 area lights, shadows turned off.

http://forums.newtek.com/attachment.php?attachmentid=134100&d=1471495075

Notice how the area lights with shadows turned off start to remove the detail of the Radiosity occlusion.

Putting that back with Occlusion shader:

http://forums.newtek.com/attachment.php?attachmentid=134101&d=1471495633

And finally taking AO off and turning on the shadows for the Area Lights:

http://forums.newtek.com/attachment.php?attachmentid=134102&d=1471495713

To my eyes probably the most pleasing to the eye of all, considering for an interior scene you do have to add some lights.

And for he record. Adding AO shader took significantly longer to render than the last image and it is still far more noisy.

Hope this information is useful.

Snosrap
08-18-2016, 07:11 AM
Yeah there are a lot of ways to deal with contact issues. I remember back in the day when soft shadows could only be accomplished with spotlights and shadow maps - talk about contact issues. :) That's what I like about some of the newer renderers available today, these issues are pretty much a thing of the past. This is one of the reasons I'm so anxious to get my hands on the new LW so I can test it's new render engine and make a decision as to whether to stick with native or invest in a 3rd party product.

rustythe1
08-18-2016, 08:26 AM
yes, I nearly always just use area lights now, often don't even bother with radiosity, just set the lights to an inverse/2 falloff, default 1m, colour space srgb, and then pump the light and or shader samples up until its clean, I find those two settings add far less render time than any of the radiosity settings, and often just a 4x aa will give good results as long as the samples are high enough, I have had archviz images that taking samples from 6 to 24 samples on lights have only added a second or so to render times,

Surrealist.
08-18-2016, 09:30 AM
Interesting. Additionally if you exclude the roof or ceiling object from the DP Dome light you have that to add some fake AO as well on an interior.

jasonwestmas
08-18-2016, 09:46 AM
Especially in lightwave, I find that setting up multiple lights including dome lights creates a pleasing "global lighting" effect without the GI hit. The only thing you are missing is the color bleed stuff. I'm sure most compositors have a way around that.

In a stylized context I tend to use colored lights which appears to add enough visual interest in my case.

rustythe1
08-18-2016, 10:40 AM
also remember you can change the shadow colour of each light, that helps bring out details in the shadows setting it to not pure black

Tobian
08-18-2016, 10:40 AM
Step 1, set ambient intensity to 0%

My work here is done! :D

jasonwestmas
08-18-2016, 10:49 AM
Step 1, set ambient intensity to 0%

My work here is done! :D

yeah that does help a lot for getting good contrast.

jeric_synergy
08-18-2016, 10:54 AM
You guys' ability to stay awake long enough (I'm not talking time of day, but boredom threshold) to test all that out is mind boggling to me.

Frankly, I'm just happy when they put a black blob underneath Bugs Bunny as a shadow.

Snosrap
08-18-2016, 11:16 AM
Step 1, set ambient intensity to 0%

My work here is done! :D

Yep - that goes without saying. :) Remember when it defaulted to 25% - yow!