Computer Graphics Imaging Lectures 5 and 6 Scene Management Basic Modeling Techniques

Scene Management Scene: – A way to organize your objects – Scenes can share objects Add a new scene – Four options: empty, link Object, link ObData, and Full copy Link object to a scene – Ctrl+L

Outliner Outliner window helps you navigate a complex scene If you see an empty outliner window, select “View” and then “Show Active” LMB to select Can toggle object level restrictions Search by name: ctrl + F

Oops Diagram Select “View” and then “Show Oops Schematic” to see the object relationship diagram

Content of your Blender file To see the content of your Blender file – Shift + F4 Screen layout is stored in your Blender file – Can choose to load only the scene and not the UI layout

Append or Link How to merge multiple Blender files? – File  Append or Link (Shift + F1) Can append or link object, mesh, lights, material, texture, etc. Linking – Can only modify linked objects in the original Blender file – Useful when working as a team

Basic Modeling Techniques Working with objects Erase: x or DEL Join: ctrl + J Separate objects – In Edit mode, select the points or faces to be separated, then press P

Selection – RMB – Multiple selection: Shift + RMB – Border select: B – Lasso Select: ctrl+LMB – Menu selection Multiple selection: shift + RMB Deselect: shift + RMB on the selected object Deselect all: press A

Moving objects Move: – Press G – Axis constraint: G + (x or y or z) – Move one Blender Unit (BU) at a time: ctrl + mouse motion – Slow motion: shift + mouse motion – Move 1/10 of BU: shift + ctrl + mouse motion

Rotation Select and press R Axis constraint: press X or Y or Z Rotate along local axis: R and then press X (or Y or Z) twice Trackball rotation: R + R

Scaling Press S Axis constraint: press S and then X or Y or Z In Edit mode, press Alt + S to scale selected vertices along the direction of the normals

Cloning Alt+D – Or menu: Object  Duplicate Linked Cloned objects share the same mesh, but can be individually transformed

Duplicate Shift + D – Or Menu: Object  Duplicate Differences between Clone and Duplicate – Clones share mesh – Duplicates don’t share mesh, but share materials, texture, etc. Can see the relationships clearly in the Outliner view or Oops diagram.

Parenting and Grouping Select objects and press Ctrl + P The last object selected is the parent Child objects will follow their parent objects Remove parent-child relationship – (select only child objects) and then Alt + P Grouping – Ctrl + G

Tracking – Ctrl + T Undo tracking – Alt + T – Or select the tracking object, press F7 (object), and delete the tracking constraint.

Undo and redo Undo: ctrl + Z Redo: shift + ctrl + Z or ctrl + Y History: Alt + U

Mesh editing Switch between object and edit mode – Tab

Subdivide surface Press w, and select “Subdivide” or “Subdivide Multi”

Smooth a surface Press W and select smooth – Smooth out the polygon mesh – Will slightly change the shape of polygon mesh Do not mistake it for the “Set Smooth” button under the Editing panel (F9) – “Set Smooth” means set smooth shading. – Does not change the shape of polygon mesh

Select vertex, line, or face Select mode: ctrl + tab Can also select from icons Edge and face loop selections – Alt + RMB

Selections in Edit mode Point selection: RMB Border select: B Circular region: B + B – Use mouse wheel to control the size of the circle Lasso region (hand drawn region) select – Ctrl + LMB

Basic mesh modeling Extrude Mirror Spin SpinDup Warp

Extrude In Edit mode, select one or more vertices/lines/faces, Press E – LMB to confirm – Esc to undo One of the most useful editing techniques Another way to add vertices to the scene – Select a vertex, then ctrl + LMB

Mirror In Edit mode: press M, then press X, Y, or Z In Object mode: press ctrl + M, then press X, Y, or Z The selected object will flip along X, Y, or Z axis to the other side of the pivot point Don’t mistake this for Mirror Modeling

Spin Useful tool for creating axially periodic structures (e.g. cup, plate, vase, etc.) Create a profile of the object Select all the vertices of the profile Choose the pivot point (e.g. 3D cursor) The spin axis will be perpendicular to the current view (e.g. top view) In Edit mode, under Editing (F9) panel, press the Spin button

Spin Dup Create multiple copies of an object around a circle In Edit mode, under Editing (F9) panel, press the Spin Dup button Objects created by Spin Dup are considered as one entity – Separate them individually, if necessary.

Knife Add new edges on the faces of an object Select the edges or faces you want to “cut” – Nothing will happen if “cut” unselected edges/faces In Edit mode, press K – Select different types of cuts – Draw the line – Enter to confirm, Esc or RMB to cancel

Edge slide In Edit mode, select an edge Press ctrl + E, then select edge slide

Bevel In Edit mode, press W and then select Bevel Each edge will be split into two parallel edges and you can slide them Purpose: to create smoothed edges

Vertex group and weight paint Will talk about them when we discuss Armature based animations

Subsurf modifier In Edit mode, under Editing (F9) panel A modifier is an operator that you can apply to the mesh model to change its appearance. – The change is not permanent till you press “Apply” in the object mode – Can use multiple modifiers to an object Note the difference between the “Subdivide” button and the “Subsurf modifier”

Subsurf modifier Surface subdivision – Start with a low resolution model – Use subdivision to recursively generate higher and higher resolution models – Don’t over do it: more polygons means longer rendering time! For a little more detail, check out ace ace

Mirror Modeling A useful technique to model symmetrical objects (e.g. faces, etc.) Two approaches – Use a Mirror modifier to mirror modeling on a single object – Create two clone objects and make them mirror each other

Mirror Modeling Mirror Modifier – Select the object – Add a Mirror modifier under the Editing panel (F9) – Choose the mirror axis The mirror modeling will happen along this axis The mirror plane is perpendicular to this axis – Now it’s ready for mirror modeling – Press Apply button to make the changes permanent

Mirror Modeling The “Cloning” approach – Select one object This will be the “half” object – Press Alt + D to create a clone They will share the same mesh model – Move the clone to the left or right – With the clone object selected, press N In “Transform Properties”, set ScaleX ( or ScaleY, or ScaleZ) to -1.0 – Now they are ready for mirror modeling – Join the two objects to make the changes permanent

Sculpt mode Select “Sculpt Mode” from the “Mode” menu Under the “Sculpt” panel, can select different “Brushes” – Modify an area of the mesh with a “Brush” – E.g. can “Smooth” or “Flatten” the mesh