How would you create this kind of snow accumulation?

[ploytv]

How can I create this effect, where snow seems to be accumulating behind these rocks?
I tried different approaches, like negative removal rates in the heightfield_erosion Sop. Nothing seems to work.

I can remember that I once saw a tutorial on exactly this, but I can`t find it anywhere.

I think this kind of snow pile up is whats missing from a lot of snowy mountains, created in 3d.

Any help would be greatly appreciated!

[konstantin magnus]

Hi Ploy,

you could streak the object mask on towards the gradient.

  

heightfield_snow.hipnc

Edited March 11 by konstantin magnus

[ploytv]

WOW! Thank you, thats exactly what i was looking for! 

I really appreciate your help!

[HM_2020]

On 3/10/2023 at 10:58 PM, konstantin magnus said:

Hi Ploy,

you could streak the object mask on towards the gradient.

  

heightfield_snow.hipnc 286.72 kB · 27 downloads

great stuff, had to have a quick play with that!

heightfield_snow.hipnc

[konstantin magnus]

18 hours ago, HM_2020 said:

great stuff, had to have a quick play with that!

Cool, I've just replaced the iterative approach by a tracer that does practically the same thing.

int steps = chi('steps');
float w = chf('width');

float dist = 0.0;
if(f@mask < 0.5){
    vector pos = v@P;
    for(int i = 0; i < steps; i++){
        vector grad = volumegradient(0, 'height', pos);
        pos -= normalize(grad) * w;
        float mask = volumesample(0, 'mask', pos);
        if(mask > 0.5){
            dist = 1.0 - i / (steps - 1.0);
            break;
        }
    }
}

f@mask = max(f@mask, dist);

 

snow_accum.hipnc

[hannes603]

you can also use particles and let them rise along the mountaines surface.

mountain_snow.hip