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

Objective of Step 1.3:

To learn

•how to open and close the Part-Editor.

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

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

•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 Base-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 graphics-area - click the Expand / Collapse icon to see the vertical toolbar

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

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

•We enable the Edit Part in Part-Editor icon

Add a Line to the Base-Part

GA-PartEditor-AddLine

STEP 1: Start the Add Line command

+ Line

1.Expand the vertical Geometry toolbar to the LEFT of the graphics-area

2.Click Geometry toolbar > Add Line

The Add Line command is active. Your pointer is now the Add Line pointer.

STEP 2: Add the Line

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

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

Reminder: Drag is...

In the graphics-area...

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

The Line is now in the Part.

Line in graphic-area

Add Coincident Constraints

You can now add constraints and dimensions to locate the Line.

Usually, add constraints before you add dimensions.

GST-1-3-4

STEP 1: Start the Add Coincident Constraint command

You want a Point* at the end of the Line to be on the X-axis of the Base-Part.

1.Expand the vertical Constraints toolbar to the RIGHT of the graphics-area.

2.Click Constraints toolbar > Add Coincident Constraint

You must click two elements to add a Coincident constraint.

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

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

IMPORTANT

If you attempt, but fail, to click the Point* and/or the X-axis, you must click the two elements again.

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

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

TOP-TIP

Increase the Symbol Size and Selection Size so that it is easier to see and select a symbol in the graphics-area.

Edit menu > Application-Settings > Accessibility tab > Graphics > Symbol Size (6) / Symbol Selection Size (8)

Add Coincident Constraint

Drag Points along the Axes

STEP 2: Add a Coincident constraint, again

You also want to constrain a Point* at the other end 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.

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

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

STEP 3: Deselect Coincident Constraint

1.Click Add Coincident Constraint to deselect it.

You can drag each Point along each axis.

How to delete a Constraint

GST-1-3-12

You cannot see constraints in the graphics-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 that you want to delete

3.Click Delete element in the shortcut menu.

If you do delete the constraint, then to continue 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 graphics-area

2.Click Geometry toolbar > Add Dimension

The pointer changes to Add Dimension.

STEP 2: Add a Dimension

1.Click the Point on the Y-axis

2.Click the X-axis

The dimension is next to your pointer.

3.Click the graphics-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 on the X-axis

2.Click the Y-axis

The dimension is next to your pointer.

3.Click the graphics-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, not –120. See below: Why is the Dimension negative?

Note, If the number is –100, you need to click the Left Spin-Box arrow to decrease the value to –120.

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 select them to add a dimension.

A Line has a coordinate system : an Origin, +X-axis, and a +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, therefore, they also have their own Coordinate-Systems.

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 the Point is in the +Y-axis direction of the Y-axis

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

In top image, when we click the X-axis and then a Point that is below the X-axis (c or d in the green area), the dimension is negative. As expected.

In bottom image, when we click the Y-axis and then a Point that is anywhere in the +X-axis area (c or d in the green area), the dimension is negative. Less expected!

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 a command is active - even if Add Dimension is the active command.

STEP 1: Clear all Commands

1.Click the active command to deselect it

In this case, click the Add Dimension command.

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

1.Right-click your mouse.

GST-1-3-13

GST-T1-3-RoundDimension

STEP 2: Edit the Dimension

To edit a dimension, we recommend you click the arrowhead of the Dimension you want to edit - it is easy to click.

1.Move you mouse-pointer over the arrowhead of the Dimension. The color of the dimension should be the selected color.

2.Double-click

1.Click the arrowhead one time

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 use to close the Part-editor.

For example:

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

1.Double-click a sketch-element (e.g. the Line ) in the Part.

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

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

3.Click the Edit-Part in Editor-Part (or Toggle “Edit-Part” ) at the top of the shortcut menu.

Edit Part in Part-Editor command

1.Disable Edit Part in Part-Editor (or Toggle “Edit-Part” ) 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, and Part Not Solved.

The Line in the Mechanism-Editor

The default colors of a sketch-element (for this Dark Charcoal Theme) in the Part-Editor:

Blue (or similar), indicates it is Under-Defined.

Green (or similar) indicates it is Fully-Defined.

The color of sketch-elements in a Part after you close the Part-Editor. are the same color as the Part-Outline of the Part to which you added the sketch-elements.

That is, in a Mechanism-Editor:

If the Part-Outline* of a Part is Green (or similar), then the color of the sketch-elements in the Part are also Green.

If the Part-Outline* of a Part has a Blue (or similar), then 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 and sketch-elements.

In the Mechanism-Editor:

•The Base-Part has a rectangular Part-Outline

•The Part-Outline is Green - it is the color of a Solved Part

•The Line is a sketch-element in the Base-Part. Therefore, it is also Green.

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