Author Topic: Shadow quality doubt  (Read 712 times)

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Offline zooropa

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Shadow quality doubt
« on: May 22, 2018, 07:58:27 am »
I am trying to improve my shadows at my render scene. I would like them to be non-blotchy and a little bit more intense.

I am aware of the solution based on reducing the pin size inside the HDRI studio. The scene has almost 650 samples now and the shadow still looks a little bit messy. I am wondering if "shadow quality" within the light tab has anything to do with this.

I tried to find information on KS online manual, but there is not information that treats the subject in depth. Does ShQuality bar only work with real-time ? If not I guess I will need to add another pin and reduce the size and increase the brightness where the one projecting the shadow is located at this moment.

I also thought about just playing with the output passes and try to manipulate the shadow in PS.

Kind regards and thanks for your advice, in case it comes.


Online MWo

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Re: Shadow quality doubt
« Reply #1 on: May 23, 2018, 11:54:10 am »
I not sure but I think a ground plane would help a lot in this case. As far as I can see it in your screen grab the scene has no ground plane.
Do you ever played with occluded ground shadow?

Hope that helps to improve your render.

Cheers
Marco

Offline zooropa

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Re: Shadow quality doubt
« Reply #2 on: May 23, 2018, 11:57:38 am »
I not sure but I think a ground plane would help a lot in this case. As far as I can see it in your screen grab the scene has no ground plane.
Do you ever played with occluded ground shadow?

Hope that helps to improve your render.

Cheers
Marco

Hi, thanks! I have a backdrop ramp. What do you mean with occluded shadows.

Online MWo

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Re: Shadow quality doubt
« Reply #3 on: May 23, 2018, 09:25:18 pm »
In the environment tab, you'll find an option for this.
« Last Edit: May 23, 2018, 11:15:14 pm by MWo »

Offline zooropa

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Re: Shadow quality doubt
« Reply #4 on: May 25, 2018, 02:49:52 am »
In the environment tab, you'll find an option for this.


I believe this is for situations where you don't have a surface as ground right? Not sure I will try. At least always thought that tab was the alternative when you do not use any type of support for your model.

I am extremely frustrated about the shadow aspect. I find tweaks, but the idea of "hacking" pins by over reduce them and cranck up the values its not satisfying me. I just wish the pins had a parameter concerning the shadow they cast.

The problem with the solution of "scale down cranck up " the pins, at least for me, is that the brightness also comes up. Even if I overlap a bigger pin at the same location....So yes you can get sharp shadows, but also change the reflections quite a lot...

I will try with a solution I found in the forum regarding the node "occlusion" and the "ground" material.

Online MWo

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Re: Shadow quality doubt
« Reply #5 on: May 25, 2018, 11:26:26 pm »
The occlusion in opacity channel of the ground shadow was useful in KeyShot 6, that haven’t the option in environment setting.


You can create very strong/sharp shadows with pins (HDRI editor) and render isolated shadows merging  all part materials to an emissive hidden from the camera. Then you have a great shadow layer for post work.


(Sorry for the short form - written on a mobile)

Online DMerz III

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Re: Shadow quality doubt
« Reply #6 on: May 26, 2018, 10:12:25 am »
Quick question, how large is your environment? And how large is your ground plane? Sometimes the shadows take forever to resolve if your using a larger than needed environment and ground (relative to your models). Not saying that is the case, but I have noticed I get clean shadows much faster if I optimize both of those settings (if you think about it, it is less "space" the CPU needs to compute)

Offline zooropa

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Re: Shadow quality doubt
« Reply #7 on: May 28, 2018, 03:45:19 am »
Quick question, how large is your environment? And how large is your ground plane? Sometimes the shadows take forever to resolve if your using a larger than needed environment and ground (relative to your models). Not saying that is the case, but I have noticed I get clean shadows much faster if I optimize both of those settings (if you think about it, it is less "space" the CPU needs to compute)

Hi, thanks for your tip.

The ground plane is: 6400 x 6400 cm
The environment is 4000 x 2000

The object is 47.2000 x 62.4573 x 47.200 cm

Do you think changing the ground size will give me nicer shadows or sharper ? I been playing with this hours and hours...
I really appreciate the tip, if you have any idea of how big should be my ground plane to achieve better results I am totally ears.

The reason why I am asking an estimative is cause my laptop takes ages....so if you have an estimative value for the size of my object it could improve the time used for this project.

Thanks a lot!!!

Online DMerz III

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Re: Shadow quality doubt
« Reply #8 on: May 29, 2018, 12:44:32 pm »
Hi, thanks for your tip.

The ground plane is: 6400 x 6400 cm
The environment is 4000 x 2000

The object is 47.2000 x 62.4573 x 47.200 cm

Do you think changing the ground size will give me nicer shadows or sharper ? I been playing with this hours and hours...
I really appreciate the tip, if you have any idea of how big should be my ground plane to achieve better results I am totally ears.

The reason why I am asking an estimative is cause my laptop takes ages....so if you have an estimative value for the size of my object it could improve the time used for this project.

Thanks a lot!!!


I would absolutely lower the size of both those parameters. I'm only speaking from my perspective, but if my object is say 10cm x 10cm , I generally go no higher than 10x that for the other settings. Depends on your scene and how much 'ground' you have in your shot of course, but I would try lowering the size of the environment and laptop and see if that resolves the shadows much faster. Let me know if it helps!

Also, I think part of the problem that was being addressed was the "shape" and appearance of the shadow, smaller pins that are also very bright will create less "soft" and grey shadows. Try turning the size of your main pin to something like 1 or 2 in size, and put the brightness of that pin to like 50 (as a starting point) and you'll see a more intense, less soft shadow immediately. Hope those two things help.

Regards,

David Merz
« Last Edit: May 29, 2018, 12:47:52 pm by DMerz III »

Offline zooropa

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Re: Shadow quality doubt
« Reply #9 on: June 13, 2018, 04:47:16 am »
Hi, thanks for your tip.

The ground plane is: 6400 x 6400 cm
The environment is 4000 x 2000

The object is 47.2000 x 62.4573 x 47.200 cm

Do you think changing the ground size will give me nicer shadows or sharper ? I been playing with this hours and hours...
I really appreciate the tip, if you have any idea of how big should be my ground plane to achieve better results I am totally ears.

The reason why I am asking an estimative is cause my laptop takes ages....so if you have an estimative value for the size of my object it could improve the time used for this project.

Thanks a lot!!!


I would absolutely lower the size of both those parameters. I'm only speaking from my perspective, but if my object is say 10cm x 10cm , I generally go no higher than 10x that for the other settings. Depends on your scene and how much 'ground' you have in your shot of course, but I would try lowering the size of the environment and laptop and see if that resolves the shadows much faster. Let me know if it helps!

Also, I think part of the problem that was being addressed was the "shape" and appearance of the shadow, smaller pins that are also very bright will create less "soft" and grey shadows. Try turning the size of your main pin to something like 1 or 2 in size, and put the brightness of that pin to like 50 (as a starting point) and you'll see a more intense, less soft shadow immediately. Hope those two things help.

Regards,

David Merz

Thanks David. I am aware of this technique, the only problem is that by applying a brighter pin (even if its small) the lighting changes.
I tried also by adding a bigger one located at the same spot to soften it, but it will always "burn" the highlights.

So in a away it compromises the highlights. I might be wrong, but i tried before. I am ok with the shadow now, I learn to like it.

The only problem is the "shape" looks little bit un-certain. Meaning...it has kind of an amorphous shape. I am able to share it privately if you want. Please find attached a sample so you can see what I am talking about.

Thanks for your helps at always.

I just hope KS can add more accurate shadows parameters without needing to "hack" the hdri studio. It might be helpful to have a shadow parameter within the hdri studio. Something that could let the user decide the sharpness/brightness of the shadow without needing to tweak pins sizes. This is a constructive opinion, I love KS, just thinking in improvements :)