Alto Cumulus tool demonstration

This is a small working video of the Alto Cumulus cloud tool.......

Altocumulus-Undulatus

First rendered output of Altocumulus -undulatus cloud....
Tried out a kind of evening time lapse cloud...

Fly Thru.........1

After 6 days of non stop rendering i had come up with a sort of cloud fly thru sequence......

Cumulus Cloud with Multiple scattering

So after working on the shape and animation of the cloud i felt that something  is missing with the look of the cloud,which is nothing but the multiple scattering of light that happens within clouds.
Below is a render which illustrates the cloud animation with the light scattering through the clouds.

 The main aim of this project is to develop a cloud system which involves no simulation but still allowing the artist to have a complete control over the look and motion of the clouds .The only issue with this system is slight jittering of metal balls that happens while keyframing the ramps.need to fix that issue.

Cumulus Cloud Modeler-Revised

 My previous post was on cumulus cloud modeller which had some issues with  sphere/shape randomization and didn't have much artistic control .so i thought of  revising the tool.
Most of the cumulus clouds will have a  sort of tubular structure with cauliflower kind of towers.
so i split the cloud  structure into
           1) Cloud Base
           2) Cloud Tower

Reference Image illustrating Cloud base and Cloud tower

              I implemented  the cloud base with three set of sphere layers copied one over the other with a horizontal tube as base.

             Similarly cloud tower is implemented by spheres copied on to vertical tube  which in turn is copied on to a line which is half the length of the cloud base tube.

              The radius of the Base,Primary and Secondary Spheres defines the entire shape of the cloud and we need a kind of control over each and every sphere.so i thought of linking my sphere radius with a ramp which actually gave me a fine control over the cloud shape.so i set individual ramps for my base cloud shape and Primary sphere radius as well.

Screen Grab of Cumulus Cloud Modeller Asset-Cloud base Parameters

Cloud Length-sets the length of the cloud
Cloud Mode  - used to switch from sphere mode to Metalball mode.

                         while modelling the cloud user can switch to sphere mode in order  to visualize the shape properly and when done with modelling user can switch to Metalball mode which will give a faster update while generating volume with cumulus Volume generator.

              
The overall shape of the cloud is controlled by these ramps.

Screen Grab of Cumulus Cloud Modeller Asset-Cloud Tower Parameters

Here is the working video of the cumulus modeller and its used in combination with cumulus volume generator( which is responsible for generating the pyroclastic look of the cloud )and i discussed about the volume generator in one of my previous post.

Below is the  animated/rendered cloud using the cloud modeller and Volume generator with low sampling divisions and hence it misses a lot of pyroclastic features.

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

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

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...

Cirrus Clouds

Clouds are of different types
1) cirrus
2)stratus
3)cirrocumulous
4)cumulus
5)cirrostratus

So  after working with satellite  clouds i tried to develop a tool that  can create Cirrus kind of clouds.
Cirrus clouds are very less dense ,thin,wispy and have a swirling kind of shape.
they often look very feathery and have hairy edges.

Reference image of Cirrus clouds

Cirrus is a Latin word which means "Curl".
     As usual i displaced the volume using a turbulent noise through a transformation matrix.We use transformation matrix  to scale, translate and rotate the frequency and amplitude of the turbulent noise.
     Then to achieve the swirling effect i used a curl noise which drives the rotate parameter of the  transformation matrix.
      To get the turbulent edges ,a turbulent noise is added which will drive the offset of the main turbulent noise.
still m unable to achieve the  hairy curls......

Satellite Clouds

As a part of my cloud system i tried to simulate satellite clouds ,which is not that bad....but still need to implement the vortex stuff  none but the cyclone clouds ...a common stuff in weather report...

Initially i displaced the volume with  a turbulent noise through a transformation matrix and used a curl noise to drive the rotate parameter of the transformation matrix.finally another turbulent noise is used to drive the offset of the first turbulent noise.Length of the position is taken and multiplied with user parameter (displacement) which will drive the amplitude of the curl noise.

LevelSet in Houdini

For the past few days i was finding a way to blend two geometries which is  something similar to the metalball kind of behavior.Then i  looked into the "levelset in production" presented by the guys from Sony imageworks which provided the exact info wat i was searching for...

since Houdini has the capability of generating SDF(Sign Distance Function)  ,i tried to isooffset the geometries and used volume mix operator  along with  the  math provided by the Sony guys....

still need to find a solution for the mesh jittering

Cloud Rendered....

The  grid based cloud system  is able to  simulate a large scale cloud system when multiplied n times ....and
here are some render test

screen capture of the the grid based cloud system.
I tried to extend Andreu lucio's work where his system has boundary issues.They seem to be in  a container so tried to apply   our fractal system in all the boundaries.Finally i added smoothing function  for all the boundaries which enables the user to create clouds with turbulent and feathered edges....

Flocking System QT C++

Well m not a programmer and this was my 1st try in c++ which was a bit successful...in  implementing  a flocking system ....

Procedural Cloud System_cloud Painter

For the past few week i was playing with Houdini volumes. i had a look at Cmivfx Houdini fractals dvd  which gave me a lot insight into Houdini volumes(especially Clouds).So i thought of building procedural system for clouds in Houdini. i decided to have two separate tools in my system

      1)Cloud painter

      2)Grid Based Cloud System

Cloud painter is a simple tool with which useer can paint clouds on a grid and generate clouds out of the painted spheres.for now i m posting the screen capture of the cloud painter tool....soon will be posting Grid based cloud system.