Accumulative Snow in a scene

Unity Engine
1

Hi everyone,

I’m new at UnityAnswers and my english is not quite good, the thing is: I’m creating a FPS game (Unity 3.4.2, mac version), and there are several snowfall scenes. I’ve created my own snowflakes in Photoshop and get the fx work fine, the only thing it misses is an accumulative effect, because all snowflakes goes through houses and terrain, you know.

I’ve tried to add a collider on the snowflake element but it didn’t worked. I’ve also experimented a couple of combinations but nothing worked as I need.

I’m new at Unity, I still didn’t get it well with the mesh stuff.

Does anyone have experience doing an accumulative snow scene?

Thanks, ; )

2

If you have a particle system for the snow, you can add a particle collider to the system and your particles will collide with the objects.

For snow to accumulate, I think you need a custom shader. Don’t know much about that.

3

Someone posted a demo of a snow accumulation shader a long while back, maybe last year? A search through the forums should find it. Basically, if I recall correctly, it added a snow texture to the top horizontal surfaces and could be increased over time.

This isn’t the one I was thinking of, but it might work. Look at the Strump Shader Editor thread’s first post: http://forum.unity3d.com/threads/56180-Strumpy-Shader-Editor-4.0a-Massive-Improvements

Here’s the one I was thinking about: http://forum.unity3d.com/threads/96520-Snowscape-Realtime-snow-environment-pack.?highlight=snow

4

Cool, i’ve missed the video. Nice work, although it needs a lot more snow and bigger flakes to change the environment than in the video. I’ve done accumulative snow a couple of times in 2D, also as a gameplay element, but never in 3D. I guess in 3D with todays performance there isn’t much of an option beside of a) a Voxelengine and b) altering some multitexturing. I liked how Drake walked through the snow in Uncharted 2, it wasn’t perfect but looked quite good compared to other solutions.

5

It seems as if substances with parameters changed over time could do this job well.

6

One of the fast/easy shader tricks is to use the normal and in the Vertex shader shift it upwards based on normals vs. vertical and the amount of desired snow (also blend to white). That handles the visuals, and since it’s all in the GPU rendering the character will still walk on the original height, making him look like he’s trudging through the snow. Then you use that same normal vs. vertical check to determine how much should be the original texture and how much should be snow.

7

I’ve followed the MrDuskling tip, I’ve added a World Particle Collider to the particle system. Thanks. : )
The snow effect in the video is really great, I’ll try to improve my own and I’ll post the results.

8

I was wondering if you figured out how to make snow accmulate in the end I have looked all over for how to and had no relats so far?

9

No, I couldn’t find any GPU-friendly method. Snow accumulates but it eats all de GPU at certain point. The solution I found was to destroy the particles in 10 seconds or so, creating the ‘ilusion’ of accumulative snow, but not real.