Sheet Lightning Design Basics - Version 3.60

What are the design cursor modes?
The 3D design environment has two cursor modes. These are the arrow cursor for command selection, and the cross cursor for 3D movement and selection. The cursor changes automatically from the cross cursor to the arrow cursor when it is moved from the 3D area to a command or menu area. The modes can also be manually switched when the cursor is over the 3D design area (i.e not over menus) by using the right click button on the mouse. It is therefore possible to be over the 3D design area in arrow cursor selection mode. If a left click selection is made on the mouse with the arrow cursor over the design area it will always zoom in to the view using the cursor position as the new zoom center (use the ZOOM command to return to the default zoom). Some confusion can arise if a 3D selection was intended rather than a command click. To allow 3D selection the cursor must be returned to the 3D mode using another right click on the mouse. This should return the 3D mode cross cursor. A left mouse click in the design area with the 3D cross cursor is used to select points, add new objects, snap to objects, snap to center lines, move 3D objects etc. In short it is used for all 3D activity. At times during design the cross cursor movement becomes retricted to a line or point in the 3D view. A sharp movement towards the menus is usually enough to jump into the menu selection area with the cross cursor. If this is difficult the mouse right click can be used to switch to command mode selection. The current 3D position and state are maintained whilst in command selection mode. Another right click is required to return to 3D design mode.
 

How do I set the design room size?
The easiest way to set the design environment room size is via the menu command 'Scene/Room Size'. Select the command and type in the Length (X), Breadth (Y) and Height (Z) of the room. The units are irrelevant. They should be what ever units you wish to use to create the design. The room size can also be adjusted by scaling using the 'Scene/Scale Room' command. Type in a factor of 2 to double the room size. Finally the room size can be automatically adjusted to comfortably accomodate a design using the 'Scene/Centre Design' command. To use this command there must be at least one object in the design. The position of the design in the room is also adjusted to centralise it.
 

How do I obtain design intersection results?
Initially 3D design objects are in outline mode. This means they appear an individual entities with ends cut square to their center line. To obtain the intersection results the 'Compute/Cut_Wire_Model', 'Compute/Cut_3D_Model' and/or 'Compute/Unfold' commands must be used. These commands generate the 3D or flat templates that are produced by their intersection with other objects. If the object has no relationship to other objects these commands cut the object square to the ends, so they look very similar to the outline objects. Relationships are created using the SNAP command during design (see 'How do I design object intersections?').
 

How do I design object intersections?
Normally to produce intersections between objects a relationship must be created between the objects (although advanced options do exist to relax this requirement). Just placing objects in close proximity is not normally enough to produce an intersection. The objects must be linked together. Linking them in this way involves the use of the SNAP command either at creation of the objects or when an object is being actively moved/dragged. There are 3 different types of relationship: BEND, TEE and JUNC. A bend relationship is an end to end link between two objects. The TEE is end to middle and the JUNC (or junction) relationship is middle to middle. Middle means anywhere but the end. The type of relationship fundamentally affect the way the objects are cut/intersected. All design and linking activity is done on the object center lines. Multiple intersections of more than two objects are handled by Sheet Lightning to any level of complexity but each relationship that exists still only involves a pair of objects. For example if we have a 3 piece end intersection each object has a bend relationship to the other two. Sheet Lightning sorts out the complexities of the intersection automatically. Intersections such as bends can be created with incompatible sizes, for example a bend intersection between two cylinders of different sizes is not feasible as a true bend. Similarly conical intersections require specifically matched sizes to produce a valid intersection. Sheet Lightning handles this by providing special matching facilities implemented during design (see 'How do I ensure the object sizes match'). To learns how to create object relationships follow these procedures: 'How to Create and Equal Tee Between Two Cylinder', 'How to Create a Bend Between Two Cylinders', 'How  to Create a Bend Between Two Cones'.
 

How do I change the section shape and dimensions of an object?
You can change the shape and dimensions of an object using the 'SECTION' command in th left hand design menu (use the 'previous' and 'next' commands to find the correct command page). This invokes a sub-menu with the section shape options. These are: CIRC, REG, RECT and ADAPTEND, ROOTEND. The other command in the list (ADAPT, PROPORT, OVAL, ROOT, DIAM, WIDTH, HEIGHT) are extensions for manipulating the same sections but do not provide any other section shapes. To change the shape or dimensions of an object:

1. Select SECTION.
2. Select the shape from the list.
3. Snap to the object in the 3D design area (snap initiated automatically).
4. Slide along the snapped object center line to choose either an end or the middle, and select.
5. Move the cursor to change the dimensions.
6. Type a dimension while the object section is active (use F5 or press numerical keys to invoke the dimension dialog).

Follow the design procedures to learn more about setting sections sizes with reference to specific examples