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Sunlight Reflection

Posted: Mon Jul 02, 2018 7:52 am
by sornr
Hello, Twilight community!

My name is Sorn and I'm still new to Twilight.
I make installation art incorporating light and I have been finding ways to simulate my art.
I am now working on a project which I need to use sunlight as medium.
The project requires using mirror to adjust the angle of sunlight at a specific time into a desired angle which the light will pass through both sides of the building and get the shape of window panes onto the projection plane
(much like Batman spotlight but with the sun, combined with trying to use small mirror to reflect sunlight into shades).
The thing is I just can't manage to find a way to reflect sunlight into a sharp beams. I tried adjusting the material settings (architectural mirror, very reflective plastic, perfect reflection) the environment settings (sun strength = 10) and changing render presets (easy6, easy10, photon map9, etc) but it seems sunlight just "dispersed" after hitting the mirror.

Can anyone give me advice on how I can make a sharp reflected ray of light/shadow?

I'm attaching the pictures that could communicate better below.

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a sketch of my work

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plan with explanation

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one of test renders, without the desired effect (there should be sunlight hitting the building)

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desired effect I get by rotating the whole project matching the reflected angle to the incident angle (not reflected by mirror, the sun got though windows and hit the projection plane directly) you can see a very strange angled horizontal line in Background

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another example of the desired effect I created by using a spotlight, but the light is not collimated like the sunlight.

I hope it's not confusing. I want to give you a big thanks even for reading it this far.

Re: Sunlight Reflection

Posted: Mon Jul 02, 2018 10:47 am
by Fletch
This is a very advanced rendering project.
Trying to test on a large model is self-defeating while learning a new software.
As far as I'm aware you will either need Easy 10, which will give caustics from Sun reflecting from a shiny surface. Or you will need to create your own high quality caustics render setting with the PMFG render settings.

Assuming you don't want to learn how to create your own render setting, you will have to use Easy10, but it gives long render times. (I suggest just using Easy10, but you could try Settings>Tech>10. PhotonMap+Caustics - Fine AA0.3 still gives blurry caustics - I think likely too blurry for your purposes.)

Again, try a very small and simple test scene with as few objects and surfaces as possible and render with Easy10 for testing/experimenting/learning.

Re: Sunlight Reflection

Posted: Mon Jul 02, 2018 11:17 am
by Fletch
First, in the Environment Dialog DISABLE "Sun Soft Shadows" so that you can get a crisp caustic (reflection or focused light from/through refractive surface)

Here's a quick test scene for your experimentation.
To render quickly with Easy10 you will need a powerful machine. :|

Re: Sunlight Reflection

Posted: Tue Jul 03, 2018 12:42 pm
by sornr
Thank you guys very much! I'll let you know when I have a progress. You are such great help!

Re: Sunlight Reflection

Posted: Fri Jul 06, 2018 8:56 am
by sornr
I've tried and I'm now interested in creating "my own" high quality caustics render setting with the PMFG render settings.
Because easy 10 does took some time. Is doing so available in hobby version? And is there a lot of topics to learn until I attain the ability?

Re: Sunlight Reflection

Posted: Sun Jul 15, 2018 11:39 am
by Fletch
There is only one setting I've found in PMFG settings that will produce caustics from Sun/Sky from the mirror in the test scene provided above.
However, that setting resulted in a very blurry caustic, not sharp.
Settings>Tech>10. PhotonMap+Caustics - Fine AA0.3 still gives blurry caustics - I think likely too blurry for your purposes
Try that render setting.

To edit the setting, it's easier and can be done within Twilight pro, but Hobby users can find any render settings' location on your computer, copy it into the "custom" render settings folder.
Change type suffix from .xml to .txt
Open in Notepad++ or similar text only editor.
Change the appropriate setting, save the file.
Change file type back to .xml
In Twilight Render dialog refresh the render settings and find your new setting in the Custom folder.

FOLLOW THIS TUTORIAL:
Subject: How to Modify Twilight Render Setting

Re: Sunlight Reflection

Posted: Wed Jul 25, 2018 3:19 am
by sornr
Thank you very much for all the help so far! Anyway, my project had been materialised and I want to show you what it is like in person.
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Re: Sunlight Reflection

Posted: Thu Jul 26, 2018 12:26 pm
by Fletch
:clap: Congratulations!
So does it reflect onto a white wall behind the building?

Re: Sunlight Reflection

Posted: Thu Dec 06, 2018 8:37 am
by sornr
I'm sorry I have been so late to this. Yes, it is reflected onto the forest and the prepared mesh sheet in the back of the building.

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