Modeling a cloud

radiance-general
1

Hi guys!
I am a student of a course about Radiance so I am quite new with the software. I looking for information an existing model of a cloud so I would like to analyses it and maybe i will try to improve it or to develop something similar.
I hope that someone could help me!
Best Regards
Eduardo Artigas

2

Eduardo,

I have done some experimentation with clouds in Radiance, and there
are two ways that seem to work.

One is to define a closed cloud volume and apply the "mist" material
to it. This mesh must be closed, watertight, and non-intersecting, and
will appear to be of constant "cloud" density. It helps considerably
if it's in the shape of a cloud. It can look something like this:

512×512 24.6 KB

The other method allows varying density throughout the cloud, but is a
lot more work. It consists of creating a large number of small,
non-overlapping cubes (a dense matrix of cubes with small spaces
between them), each with a different mist material applied to them.

1024×1024 63.3 KB

1024×1024 66.8 KB

These options seemed to create the most cloud-like volumes (with
clouds of size 1 and mist "voxels" of size ~0.01):
-ma 0.95 0.95 0.95 -mg 0.05 -ms 0.001

Mark

···

On 2/22/15, Eduardo Artigas <[email protected]> wrote:

Hi guys!
I am a student of a course about Radiance so I am quite new with the
software. I looking for information an existing model of a cloud so I would
like to analyses it and maybe i will try to improve it or to develop
something similar.
I hope that someone could help me!
Best Regards
Eduardo Artigas

3

Thanks for sharing, Mark. I'm always delighted to see someone figure out how to do something with Radiance that I have no idea how to do, myself!

Cheers,
-Greg

···

From: Mark Stock <[email protected]>
Subject: Re: [Radiance-general] Modeling a cloud
Date: February 23, 2015 11:36:28 AM PST

Eduardo,

I have done some experimentation with clouds in Radiance, and there
are two ways that seem to work.

One is to define a closed cloud volume and apply the "mist" material
to it. This mesh must be closed, watertight, and non-intersecting, and
will appear to be of constant "cloud" density. It helps considerably
if it's in the shape of a cloud. It can look something like this:
http://markjstock.org/graphics/ray/clouds04.jpg

The other method allows varying density throughout the cloud, but is a
lot more work. It consists of creating a large number of small,
non-overlapping cubes (a dense matrix of cubes with small spaces
between them), each with a different mist material applied to them.
http://markjstock.org/transfer/img2_00.jpg
http://markjstock.org/transfer/img3_01.jpg

These options seemed to create the most cloud-like volumes (with
clouds of size 1 and mist "voxels" of size ~0.01):
-ma 0.95 0.95 0.95 -mg 0.05 -ms 0.001

Mark

On 2/22/15, Eduardo Artigas <[email protected]> wrote:

Hi guys!
I am a student of a course about Radiance so I am quite new with the
software. I looking for information an existing model of a cloud so I would
like to analyses it and maybe i will try to improve it or to develop
something similar.
I hope that someone could help me!
Best Regards
Eduardo Artigas

4

Those clouds are awesome!!

Not sure if useful for you (probably not)... But, why not using HDR probes
of real skies? And maybe, with your models, find a way of creating and/or
writing artificial probes?

Bye!

···

El feb 23, 2015 4:47 PM, "Greg Ward" <[email protected]> escribió:

Thanks for sharing, Mark. I'm always delighted to see someone figure out
how to do something with Radiance that I have no idea how to do, myself!

Cheers,
-Greg

> From: Mark Stock <[email protected]>
> Subject: Re: [Radiance-general] Modeling a cloud
> Date: February 23, 2015 11:36:28 AM PST
>
> Eduardo,
>
> I have done some experimentation with clouds in Radiance, and there
> are two ways that seem to work.
>
> One is to define a closed cloud volume and apply the "mist" material
> to it. This mesh must be closed, watertight, and non-intersecting, and
> will appear to be of constant "cloud" density. It helps considerably
> if it's in the shape of a cloud. It can look something like this:
> http://markjstock.org/graphics/ray/clouds04.jpg
>
> The other method allows varying density throughout the cloud, but is a
> lot more work. It consists of creating a large number of small,
> non-overlapping cubes (a dense matrix of cubes with small spaces
> between them), each with a different mist material applied to them.
> http://markjstock.org/transfer/img2_00.jpg
> http://markjstock.org/transfer/img3_01.jpg
>
> These options seemed to create the most cloud-like volumes (with
> clouds of size 1 and mist "voxels" of size ~0.01):
> -ma 0.95 0.95 0.95 -mg 0.05 -ms 0.001
>
> Mark
>
>
> On 2/22/15, Eduardo Artigas <[email protected]> wrote:
>> Hi guys!
>> I am a student of a course about Radiance so I am quite new with the
>> software. I looking for information an existing model of a cloud so I
would
>> like to analyses it and maybe i will try to improve it or to develop
>> something similar.
>> I hope that someone could help me!
>> Best Regards
>> Eduardo Artigas

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