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DesignSpark Mechanical - Mirror symmetry with construction line

Our DSM community expert and power user, Smithy demonstrates how a simple construction line can be used to create mirror symmetric objects and manage the linked face associations in this 2-part video series. Whilst DesignSpark Mechanical (as of v5.0) lacks a one-click 3D mirror tool like traditional CAD software, there is still a lot you can do with a construction line mirror. Note that DesignSpark Mechanical Version 5.0 (Build 7232) is used throughout this demo. Chapter timestamps are embedded in the videos.

Part 1: Creating simple mirror symmetric objects

Part 2: Manage linked face associations and Advanced tips for Drawing add-on users

Essential Quick Tips - for printed reference:

The following Quick Tips lay out the essential creation principles of simple symmetric 2D shapes, pulled into a symmetric body with the description of necessary processes to add further symmetric features.

For more information, download our in-depth article.  

Tip #1: One axis Symmetry

Draw shape to complete a profile and exit sketcher.

One axis Symmetry

Tip #2: Surface into a Body

i) Select the surface (note the Mirror Plane and its icon - select it to disable mirror symmetry face linking process)

ii) Pull Surface to thicken and create Body

Surface into a Body - Select

Note the display of Mirror plane with able/ disable toggle and the texture highlighting of the 'associated linked face' upon any linked face selection.

Surface into a Body - Pull

Tip #3: Two Axis Symmetry

Two Axis Symmetry

Exit sketch. Note the 2 mirror planes and the divided overall pattern.

Select only 1 reflected segment - Pull to thicken with merge on

Select only 1 reflected segment

Note the one or two plane symmetric highlights

Note the one or two plane symmetric highlights

Tip #4: Adding Protrusions or Depressions

To an internal existing face edge

Adding Protrusions or Depressions

To an external existing face edge:

To an external existing face edge

Using a sketch plane through material thickness:

Using a sketch plane through material thickness

Tip #5: Selection Memory

To establish / recall a selection memory of faces (very beneficial when combined with Mirror / Symmetry Planes)

Selection Memory

Tip #6: Create duplicate features

Such as rounds / chamfers over mirror planes

Create duplicate features

Tip #7: Mirror / Symmetric Feature ( selected ) Deletion

i. Select the face/faces > Cut and paste

ii. Select the face/faces > Pull with mirror plane disabled

Tip #8: Mirror / Symmetry Axis Deletion

Select any face to 'show ' the relevent Mirror Plane > select the plane > Delete

Tip #9: Mirror / Symmetry - Disabling the Default Behaviour

Select the face/faces > Pull with mirror plane disabled

Thus the pulled faces will not have any mirror symmetry linking and the pulling process will not establish any other linking throughout the body.

Tip #10: Mirror Symmetry - Re-establishing / Creation of Face Linking Associations

Done through a new mirror symmetry creation process which auto-associates and links symmetric faces found about the new mirror axis during the pull operation

1) Same sized and symmetrically faces disposed about the new mirror axis

2) Aligned face 'edges' across the new mirror axis.

Tip #11: Observations on Sketch plane default XY position

Observations on Sketch plane default XY position

Note: It may be desirable to keep the original Mirror sketch lines in a Curves folder with the body - Creating the body in a component will achieve this.

Create a sketch plane on the above selected face.

Add a construction line to the X axis, set to Mirror and draw a circle

Add a construction line to the X axis

Sometimes, it's necessary to remove the Body from the display, prior to exiting the sketch (mirror on).

remove the Body from the display

Display the Body, Pull cut ONLY ONE of the circles into the Body

Display the Body - Pull cut ONLY ONE of the circles into the Body

Establishment of new with additional pre-existing symmetrical faces are now associatively linked.

Selection or mouse proximity highlights any linked associated faces

Tip #12: Example of Aligned Face Linked Pairs

Face Edge Alignments - Established throughout the body when any face is similar in size and mirror symmetrical about the face pull mirror axis.

Example of Aligned Face Linked Pairs

Tip #13: Handed Pair Bodies

Sketch ONE SIDE ONLY with the mirror line set on

Handed Pair Bodies

PULL one face only

PULL one face only

Paired Bodies must remain under owning component

Tip #14: Adding features / further designing

Adding features / further designing - pt1

Adding features / further designing - pt2

Adding features / further designing - pt3

*Important note concerning the functionality of adding mirror symmetric protrusions , depressions, holes etc. If not functioning as described:

1. Before exiting the sketcher, undisplay/hide the body.

2. Exit the sketcher (profiles must in this situation be closed)

3. Display the body, select a face, then pull, etc

RS DesignSpark is the go-to platform for students, makers, hobbyists and professional design engineers, providing design resources such as the award winning DesignSpark PCB and DesignSpark Mechanical CAD software. Join the community today at https://www.rs-online.com/designspark/register
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