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SE 313 – Computer Graphics

Lecture 2: Using BlenderLecturer: Gazihan Alankuş

Please look at the last three slides for assignments (marked with TODO)

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First, let’s figure out the exam date• We only have 14 weeks total (12 left)• In class or after class on Friday?

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Our Goal

• Introduce basic 3D computer graphics concepts using Blender

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3D world

• 2D vs. 3D– Objects are in 3D– We view them via 2D projections

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3D Coordinate System

• X, Y, Z coordinates identify the location of a point– Right hand rule

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3D Objects

• Composed of many 3D points• An objects is identified using – Position of an object reference point– Orientation of the object

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Viewing the 3D World

• Our eyes project the 3D world into 2D images

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Projecting 3D into 2D

• Take a photo and print it– 3D -> 2D

• Screen is 2D, world is 3D– Viewing the 3D world properly requires some

maneuvering – Just like walking around a car to look at it from

different positions and angles

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Viewing in Blender Using Maya Presets

• Maya presets are like Unity– Orbit (turn)

• Alt + left mouse drag– Pan (move)

• Alt + middle mouse drag– Tumble (zoom)

• Alt + right mouse drag

• Blender-specific:– Keys in the numpad for standard angles,

orthographic/projection switch, step-by-step turning, etc.

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Foundations of 3D Objects and How to Deal with Them in Blender

• Vertices• Edges• Faces• Materials– Textures

• Lights• Camera

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Simple Exercise

• Making a jumping monkey and using it in Unity

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Lab assignment• Part 1

– Create a cube and enlarge it in the x axis. This will be the house.– Duplicate the cube and move it up in y axis. This will be the roof.– Select the top face of the roof and scale it down uniformly.– Select the bottom face of the roof and scale it up uniformly (a little bit).– Select the roof and add a new material to it (this way it will not share the material with the

house).– Make the diffuse color of the roof red.– Make the diffuse color of the house blue.– Create a ground using a grid.

• Part 2– Decorate the front and the sides of your house with windows, etc. (bonus points for

creativity).• Part 3

– The assistant will ask you to show the front/back/top/bottom/left/right side of the house in an arbitrary order. You will use alt + left mouse drag to rotate the view. You have to do this quickly and accurately.

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TODO: Homework 2.a (reading)• Read and understand all of the chapters

here (they are short):– http://

programmedlessons.org/VectorLessons/vectorIndex.html

– There will be a quiz about this next week.

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TODO: Homework 2.b (deliverable)• Open the .blend file you submitted for

homework 1.• Select three objects that are distant to each other.

Select them so that they form a triangle and are not on a line. Change their colors to be red, green and blue

• Write down the 3D locations of all three of the objects. (Look at the object tab on the right pane and use the values under the location, which is under the transform heading)

• Calculate the vector VRG that is from the red object to the green object. Calculate the vector VRB that is from red to blue.

• Use cross product between these two vectors to calculate a vector that is perpendicular to the plane that your letter is in.

• Using a cylinder and a cone, draw that vector starting from the red object. Let the cone be right where the tip of the vector should be (we’ll look at its Location value). Place the cylinder such that it connects the red object and the cone.

• Submit the rendered image and the .blend file, just like you did last week. In addition, submit the details of your calculations. Your calculations should reflect the locations of objects in your .blend file.

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