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Previously i was adding blender contents across multiple pages, but that was not working well for me. So here comes the blog.

Blender 2.5x : Animating Mask Modifier

posted Mar 19, 2011, 3:21 AM by Satish Goda   [ updated Mar 19, 2011, 4:43 AM ]


  • Linked Duplicate Meshes
  • Vertex Groups
  • Animated Mask Modifier (View/Render visibility and invert property)
  • Material Slots On Object
  • Download .blend


How it was done?

Related Links

satishgoda at gmail dot com

Blender 2.5x : Lighting/Rendering : Z-Transparent Shadows Test

posted Mar 2, 2011, 1:50 AM by Satish Goda   [ updated Mar 2, 2011, 11:11 PM ]


Experiment #1

Experiment #2

Experiment #3

Experiment #4

Experiment #5

Further Reading

satishgoda at gmail dot com

Rendering Reference : Sampling and Filtering

posted Feb 15, 2011, 1:30 AM by Satish Goda   [ updated Mar 19, 2011, 1:39 AM ]

No sampling

With sampling


 Overview of Aliasing in Computer Graphics


What is Anti-aliasing?


Antialiasing and Raytracing (Must read)


Stochastic Sampling in Computer Graphics


High Quality Filtering

Reconstruction Filters in Computer Graphics

Signal Processing Chapter from the book "Principles of Digital Image Synthesis - Volume 1"

Blender Related

 Samples and Filtering


Quasi Monte Carlo Sampling and Adaptive Sampling in Blender


Full Sample Anti-aliasing


Raytraced Soft Shadows

Other Renderers

Brazil Rendering System Sampling (Nice illustrations)


Yafaray AntiAliasing Settings


LuxRender Render Settings


satishgoda at gmail dot com

Blender 2.5x : Lighting/Rendering Tests - Indirect Illumination #2

posted Feb 10, 2011, 1:49 AM by Satish Goda   [ updated Feb 11, 2011, 2:28 AM ]

Further testing.. Please refer to Blender 2.5x : Lighting/Rendering Tests - Indirect Illumination #1 for earlier experiment.

Test 1


Download .blend file

Test 2

I was doing more and more tests to understand the finer details of the algorithm used for Indirect Lighting (one bounce indirect illumination). This time around was playing with negative falloff where we can see what looks like a point cloud representation of the directly illuminated geometry.


Download .blend file

Test 3

This time around I used a light bouncing off of a textured wall. I also noticed that varying the subdivisions on the geometry has an effect on the Indirect Illumination calculation and the final image.


Please refer to Blender 2.5x : Lighting/Rendering Tests - Indirect Illumination #1 for my earlier experiments.

satishgoda at gmail dot com

Blender 2.5x : Lighting : Indirect Lighting using Mesh Lights

posted Feb 9, 2011, 2:05 AM by Satish Goda   [ updated Feb 22, 2011, 12:06 AM ]


In Blender 2.5x, mesh geometry objects can emit light (act as light sources). Without having any light source (point light, spot light) in the scene, we can still have illumination (indirectly). This feature is called Indirect Lighting (using mesh lights). On this page you will find an example of mesh lights and some notes about the technique.

Note: Another form of Indirect Lighting in blender is light (from a point or sun light source) bouncing off of objects and indirectly illuminating scene geometry. You can find examples of that at this link.

Setup #1

The following is my setup. To learn how to set a scene yourself, please click here or here

Download .blend file

In the demo video, I was experimenting with various values for the "Error" attribute, ranging from small values (for which the mesh lighting is smooth) to large values (where the mesh lighting is blocky)

Setup #2 : Cornell Box

The Cornell model was provided by my friend Tejas Trivedi

Download .blend file

I did various test renders and documented the values used in the following slide show ...

An older experiment

I did the following test when the feature was first added in Blender

Related article:
Blender 2.5x : Lighting/Rendering Tests - Indirect Illumination

Further Reading

satishgoda at gmail dot com

Blender 2.5x - Lighting/Rendering Tests - Realtime Rendering in Viewport

posted Jan 30, 2011, 5:49 AM by Satish Goda   [ updated Feb 4, 2011, 11:30 PM ]

Under Construction. Please check back later :-)

About this test




Related Articles

satishgoda at gmail dot com

Blender 2.5x : Scripting : Getting the World Coordinates

posted Jan 29, 2011, 5:36 PM by Satish Goda   [ updated Mar 14, 2013, 2:52 AM ]

A question was asked on Learning Blender 2.5 Facebook page about the process of getting the world coordinates of a control vertex on a curve. Following was my answer

How do we visualize the local and world coordinates for object location, vertex location?

Note: For all the examples on this page
  1. I have used a BezierCurve object with three control vertices.
  2. The curve object has been translated along the +x direction by 1 unit and also rotated it around in space.
  3. The curve object is not parented to any other object.

Local coordinates of the control vertex

The control vertex's local coordinates are those values that are stored with respect to the curve objects transformation (in other words, in Object Space)

The Local Coordinates will be different than the Global Coordinates, If the object to which the vertices belong has been transformed (scaled, rotated, translated)
Global (World) coordinates of the control vertex

The control vertex's global/world coordinates are those values that are obtained after taking into consideration the transformation of the curve object. These values are with respect to the World Coordinate System in Blender.

The Local Coordinates and World Coordinates will be the same if the object is not transformed.

Since the time this tutorial was written, the order of operations for multiplying matrices and vectors/points has changed in Blender. Please follow the code at the link below for the updates.
Updates to the tutorial

How can we do it using Python?

Copy/Paste the code

import mathutils

wmtx = bpy.context.active_object.matrix_world

localCoord =[0].bezier_points[1].co

worldCoord = localCoord * wmtx

To learn more about vector and matrix operation that you can perform, read the manual

Blender 2.5x : Scripting : Select Control Points of a Curve Using Python

posted Jan 28, 2011, 12:19 PM by Satish Goda   [ updated Jan 30, 2011, 9:01 AM ]

On, someone asked this question and this was my solution. Having never tried this before, it was a nice challenge for me figure it out. It was not that hard actually, thanks to the new Blender Python API.

So I created a bezier curve with three control points. Then the following two methods easily answered the question..

First Method

 Selecting control points using Python : Method 1

So what is going on here?

By running the command below, we are storing the active object (at index zero) in "curve".

curve = bpy.context.selected_objects[0] 

The following command prints out the number of splines that compose the curve object. In the screenshot above, the curve object consists of only one spline.


We get an answer of 1.

We are now printing the number of bezier points that are present in the first spline object (at index zero).


We get an answer of 3.

The following commands selects the first and third control point in the 3D View. The first CV is at index 0 and the third CV at index 2.[0].bezier_points[0].select_control_point = True[0].bezier_points[2].select_control_point = True

Second Method

Selecting control points using Python : Method 2

And what is happening in this second method?

While in the previous case we used "bpy.contect.selected_objects[0]" to get access to the active object, in this example we are getting the access directly using "bpy.context.active_object". Rest of the code is same as the first example.[0].bezier_points[0].select_control_point = True[0].bezier_points[1].select_control_point = True[0].bezier_points[2].select_control_point = True

Video demonstration

Hope this helps.

satishgoda at gmail dot com

Sculpting Tools Test

posted Jan 27, 2011, 7:43 AM by Satish Goda   [ updated Jan 27, 2011, 7:48 AM ]

Had a quick stab at sculpting using 2.5x toolset. Used various brushes to achieve the following look. To give it a better look, added two lamps with different color temperatures. Rendered in the 3D Viewport using GLSL shaders.

satishgoda at gmail dot com

My Video Tutorial Recording Workflow

posted Jan 24, 2011, 7:46 AM by Satish Goda   [ updated Jan 24, 2011, 7:56 AM ]

The following post details the tools that I use for recording my video tutorials. It also lists all the tools that I evaluated before settling on couple of them that seen to get my work done.

BB FlashBack Express (Free registration key)

Can record audio from microphone, speakers and also Picture in picture (from my webcam)

WinFF/FFMpeg   (Video encoding)

This is a front end to the ffmpeg software. Very easy to use.


List of tools i recently tried and found satifying for my needs (I am using Winidows 7 OS)


Opensource, but the picture in picture (webcam capture was not working for me)

Jing (Screenshots and Screencasts)

Records upto 5 minutes in swf format. With the Pro version can record directly to mp4. I am using this for taking screenshots

TechSmith Video Codecs

Optimized for screencasts, TechSmith video codecs provide lossless image quality combined with the smallest file size possible.


Free Flash SWF/FLV Converter (Convert swf's from Jing to Avi)


Its an instant screencast creator designed to work with Twitter. You launch the recording from the website and can record upto 5 minutes. Once the recording is done, it processes it and you are good to tweet your creation. On top of that you can upload the video to youtube and download a mp4 to your computer.
I made some test recordings and you can check them out at

You can check my YouTube channel for some of my recordings.

satishgoda at gmail dot com

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