Shadow and Sun Light Analysis

[Hanys]

Hi all,

Do you have some ideas how to make Shadow and Sun analysis in H17.5? I would like to make the analytic tool for my procedural city, similar to this: 

I think it would be "sun" vector promoted to objects attributes as color. Maybe some use of new measure node?

Thank you for any advices.

 

[ikoon]

Hi, maybe this approach might work:

int count = npoints(1);

for (int i = 0; i < count; i++)
{

    vector camP = point(1, "P", i);
    vector dir = normalize(camP - @P);
    float bias = 0.01;
    
    vector hit_ps[];
    int hits = intersect_all(0, @P, dir * 100, hit_ps, {}, {});
    if (hits && distance(@P, hit_ps[-1]) > bias)
    // or just check number of intersections:
    // if (  length(hits) >1   )
    {
        @Cd *= 0.6;
    }

}

 

cull.hiplc

Edited April 5, 2019 by ikoon

[konstantin magnus]

Would anyone know a simple formula to very roughly approximate the sun path (or rather sun vector)?

 

 

Edited April 6, 2019 by konstantin magnus

[Hanys]

Nice sun path app:

https://drajmarsh.bitbucket.io/sunpath3d.html

[konstantin magnus]

General Solar Position Calculations

https://gml.noaa.gov/grad/solcalc/solareqns.PDF
https://jasmcole.com/2020/07/26/shady-business/

Edited May 21, 2021 by konstantin magnus