Monday, October 31, 2011

Cumulus Cloud Modeller

After Reading the article about the clouds in RIO i thought of making a simple modelling tool that enables the artist to model the clouds in a easier way.Most of the cumulus clouds will have a tube (oriented in X axis) kind of structure which will be flat at the bottom.

Reference Image


The Basic idea is to scatter spheres on a tube whose radius will be controlled by the user with a Ramp which enables the artist to visualize the cloud's shape  through the curves in the ramp.
In order to get the bumps and canyons another sphere is scattered over the previous one.So the tool has two layer Back to back with Two Ramps individually controlling the sphere radius.

Cumulus cloud Modeler-geometry

Cloud Rendered
Below is a small tool demonstration of cumulus cloud modeller


Monday, October 17, 2011

Altocumulus clouds

Alto cumulus clouds are mid-level layers or patches of cloudlets in the shape of rounede clumps, or rolls.They are usually white or  grey and they side away from sun.These clouds very ocassionally cause rain.
Alto cumulus cloud tool that i had developed can simulate two types
1)Undulatus
2)Floccus


 UNDULATUS

Reference Image of alto cumulus-Undulatus cloud

Undulatus are the cloudlets that are arranged in nearly parallel lines.


     Though clouds exhibit a lot of variations they follow a pattern .so  in the above shown image cloudlets are distributed in a parallel fashion .
    In order to achieve this effect, instead of direct working on volumes i created  patterns in the VOPCOP .
   Then Data from VOPCOP is sent to VOPSOP (and i should really thank Ari Danesh for suggesting me an idea to import data from VOPCOP  into VOPSOP).
   In VOPSOP i generate pscale attribute where metaballs are  being copied to , based on the data from VOPCOP.

VOPCOP PATTERN IMPLEMENTATION


Pattern for Undulatus cloud Procedurally
Generated in VOPCOP
1 )      The Global variables Pixel Horizontal Position and Pixel Vertical Position are converted to vector as all the noise position deal with vectors.
2)       Then they are plugged into the position of the curl Noise through a tranform Matrix .From there they are plugged into Ramp VOP.
3)       A Fit range VOP is added to controll the width of the stripes.
4)     Again the global variables PHP and PVP are plugged into the position of the trubulent noise.the output from the fit range node  will drive the amplitude of the turbulent noise.
5) Curl Noise is used to bring the curvy and bit irregular parallel pattern.
Screen capture of Undulatus cloud done using VOPCOP and Metal Balls



FLOCCUS

Reference Image of alto cumulus-Floccus cloud
Cloudlets with cumulus kind of tufts with raged bases.





VOPCOP PATTERN IMPLEMENTATION


Pattern for Floccus cloud Procedurally
Generated in VOPCOP
1)  As done in in the last case the PHP and PVP are converted to vector from float and plugged into the position of a curl noise .Again the converted vector is plugged into Vein VOP which will drive the  amplitude of the curl noise.

2)Since the Floccus exhibits a kind of cellular pattern i used a Rounded hexes VOP with which i can imitate the pattern.the o/p from the curl noise is converted back to float and the first two components are plugged into S offset and T offset parameters of the Rounded Hexes VOP.

3)A complement of the Rounded Hexes is taken and plugged into the main turbulent noise operator.


Screen capture of Floccus cloud done using VOPCOP and Metal Balls











Saturday, October 1, 2011

Cumulus clouds and Ice Fallout



CUMULUS CLOUDS
Cumulus clouds are formed due to Thermal convection.Their life span is very short which lasts for only few minutes .when new one grows the old one vanishes.The noise pattern for this cloud has a cauliflower kind of structure.

Reference:Cumulus cloud


The  noise pattern that can produce such an effect  is called as pyroclastic noise which google doesn't know.Then I came across Jerry Tessendorf's Siggraph course notes on cloud modelling which gave me an insight about the structure and implementation of cumulus clouds.

I should thank Serg,Luoquilin on odforce for their valuable suggestions .



I tested  the cloud with two different lighting conditions...well it  looks good even in the viewport.
Since i have some issues with the system resource i m unable post the final render.
Again i tested the cloud with a background ..the above image is a view port screen grab..

ICE FALLOUT
  Ice fallout is formed when the residual water cloud left by this one has evaporated leaving only the falling frozen particles.


 Soon i will be posting the tool demonstration and rendered output...