Getting Started Tutorials - MechDesigner > Tutorial 1: Add a Part that Rotates - a Crank

Objective of Step 1.3:

•How to open and close the Part-Editor.

•How to add and delete a sketch-element, constraints and dimensions.

•Learn that some dimensions are negative - it is a MechDesigner rule!

•Learn that sketch-elements change their color when they are fully defined.

Video

Open the Part-Editor to edit the Base-Part.

You use the Part-Editor to add geometry* to a Part.

* Geometry includes sketch-elements, constraints, and dimensions.

Double-click the Base-Part

STEP 1: Open the Part-Editor

Use the Double-click method

1.Double-Click the rectangle that is the Part-Outline of the Base-Part.

Details of a Part in the Part-Editor

The Part-Editor

The Part - when it is open in the Part-Editor:

•We do not show the Part-Outline

•The small XY-axes change to large XY-axes

•The Geometry toolbar is to the left of the graphic-area - click the Expand / Collapse icon to see the toolbar icons

•The Constraints toolbar is to the right of the graphic-area - click the Expand / Collapse icon to see the toolbar icons

•The mouse-pointer changes to the Edit Part pointer.

•The Edit Part in Part-Editor icon is enabled

Add a Line to the Base-Part

GA-PartEditor-AddLine

STEP 1: Start the Add Line command

+ Line

1.Expand the Geometry toolbar to the LEFT of the graphic-area

2.Click Geometry toolbar > Add Line

Your pointer changes to the Add Line pointer

STEP 2: Add the Line

1.Drag with your mouse-pointer in the graphic-area

The drag technique to add a Line is identical to that for Add Part.

Reminder: Drag is...

Mouse-button down...move your mouse-pointer...mouse-button up

The Line is now in the Part-Editor.

Line in graphic-area

Add Coincident Constraints

You must now locate the Line in the Base-Part with constraints and dimensions.

Usually, add constraints before you add a dimensions.

GST-1-3-4

STEP 1: Start the Add Coincident Constraint command

You want the end of the Line to be on the X-axis of the Base-Part.

1.Expand the Sketch Constraints toolbar to the RIGHT of the graphic-area.

2.Click Sketch-Constraints toolbar > Add Coincident Constraint

You must click two elements to add a Coincident constraint.

1.Click the end-Point* of the Line that is near to the X-axis

2.Click the X-axis (equivalent to a Line.)

IMPORTANT

If you attempt, but fail, to click the X-axis, you must click the two elements again.

* start-Point or end-Point of the Line.

The end-Point now has a Coincident Constraint with the X-axis.

TOP-TIP

Increase the Symbol Size and Selection Size so that it is easier to select a symbol.

Edit menu > Application-Settings > Accessibility tab > Graphics > Symbol Size / Symbol Selection Size

Add Coincident Constraint

Drag Points along the Axes

STEP 2: Add a Coincident constraint, again

You also want to constrain the start-Point* of the Line to the Y-axis.

If necessary, select Add-Coincident Constraint again...

As before, you must click two elements to add a Coincident Constraint.

1.Click the Point* that is near to the Y-axis

2.Click the Y-axis

IMPORTANT

If you attempt, but fail, to click the Y-axis, you must click the two elements again.

* start-Point or end-Point of the Line.

The start-Point now has a Coincident constraint with the Y-axis.

STEP 3: Deselect Coincident Constraint

1.Click Add Coincident Constraint to deselect it.

You can drag the Points along the axes.

How to delete a Constraint

GST-1-3-12

You cannot see constraints in the graphic-area.

To delete a constraint

1.SHIFT+Click the sketch-element from which you want to delete the constraint.

The sketch-element and its constraints are now in the Selection-Window.

In the Selection-Window:

2.Right-click the constraint you want to delete

3.Click Delete element in the shortcut menu.

If you do delete the constraint, then for the purposes of this Tutorial, add the constraint again!

Press the CTRL+Z key combination.

Shortcut menu

Add Dimensions

Select Point and X-axis to add a dimension

Dimension dialog

STEP 1: Start the Add Dimension command

1.Expand the Geometry toolbar to the LEFT of the graphic-area

2.Click Geometry toolbar > Add Dimension

The pointer changes to Add Dimension.

STEP 2: Add a Dimension

1.Click the Point that is coincident with the Y-axis

2.Click the X-axis

The dimension is next to your pointer.

3.Click the graphic-area to locate the dimension.

The Dimension dialog opens immediately

STEP 3: Edit the dimension

1.Edit the Dimension = 50.00 mm

Use the Spin-Box tool or enter it directly with your keyboard.

2.Click the Enter key on your keyboard.

Add a Dimension

STEP 4: Add one more Dimension

1.Click the Point that is coincident with the X-axis

2.Click the Y-axis

The dimension is next to your pointer.

3.Click the graphic-area to locate the dimension.

The Line changes its color when the Line is fully-constrained.

Note the Negative Dimension

The Edit Dimension dialog opens immediately

STEP 4: Edit the dimension

1.Edit the Dimension = –120 mm

The dimension is 120mm in the sketch.

See below: Why is the Dimension negative?

Why is the Dimension negative?

GST-Negative-DimA

Coordinate System of a Line, or the Part's Y-axis.

The X-axis and the Y-axis are treated as Lines, when you add dimensions

Lines have a coordinate system, which controls its origin, +X-axis, and +Y-axis.

•The origin of a Line's coordinate-system is its start-Point.

•The +X-axis direction is from the Line's start-Point to its end-Point.

•Its +Y-axis direction is +90º from the +X-axis, and on the Mechanism-Plane

Important - the X-axis and Y-axis are also pseudo-Lines, and each axis has its own Coordinate-System.

The +X-axis of the Y-axis is the Y-axis !

When we add a dimension between the Y-axis and Point: we must remember

•the dimension is positive when it is in the +Y-axis direction of the Y-axis

•the dimension is negative when it is in the –Y-axis direction of the Y-axis

In the image, when we click the Y-axis and then a Point in the green area, the dimension is negative.

GST-Negative-DimB

To edit a Dimension

When you add sketch-elements and Dimensions, you also need to edit dimensions.

You cannot edit a dimension if there is an active command - even if Add Dimension is the active command.

STEP 1: Clear all Commands

1.Click the active command

In this case, the Add Dimension command.

1.Click the ESC (escape) key on your keyboard.

GST-1-3-13

GST-T1-3-RoundDimension

STEP 2: Edit the Dimension

We recommend you click the arrowhead of the Dimension you want to edit.

1.Move you mouse-pointer over the arrowhead of the Dimension

2.Double-click to open the Dimension dialog

1.Click the arrowhead one time, then

2.Right-click the Dimension in the Selection-Window

3.Click Edit element in the shortcut menu.

The Dimension dialog is open.

STEP 2.Edit the Dimension

1.Edit the Dimension in the normal way

Close the Part Editor

You must close the Part-Editor to return to the Mechanism-Editor.

Close the Part-Editor

Right-click in graphic-area

STEP 1: Close the Part-Editor

There are many methods you can do to close the Part-editor.

For example:

1.Double-click the Y-axis of the Part.

1.Double-click any sketch-element (the Line ) in the Part.

1.Click the graphic-area, to make sure the Selection-Window is empty

2.Right-click your mouse-pointer in the graphic-area

3.Click the Edit-Part in Editor-Part at the top of the shortcut menu.

Edit Part in Part-Editor command

1.Disable Edit Part in Part-Editor command above the Geometry toolbar

You are now in the Mechanism-Editor again.

Save your Mechanism with CTRL+S

Colors of Sketch-elements in the Part-Editor and Mechanism-Editor

See Application-Settings > Graphics tab > Graphic Colors | Geometry Fully Defined / Geometry Under Defined / Part Solved / Part Not Solved

The Line in the Mechanism-Editor

The default colors of a sketch-element (for this Dark Charcoal Theme)

Part-Editor: a Blue (or similar) sketch-element indicates it is Under-Defined.

Part-Editor: a Green (or similar) sketch-element to indicates it is Fully-Defined.

The color of sketch-elements that are in a Part

Mechanism-Editor: if a Part has a Green (or similar) Part-Outline* - the color of the sketch-elements in the Part are also Green.

Mechanism-Editor: a Part has a Blue (or similar) Part-Outline* - the color of the sketch-elements in the Part are also Blue.

* We will discuss the colors of a Part-Outlines in Step 1.5.

The Base-Part

The color of the rectangle that is the Part-Outline of the Base-Part is Green.

In the Mechanism-Editor, the sketch-elements that are in the Base-Part are also Green.

Step 1.3: Edit the Base-Part, Add a Line