Sketcher

Sketcher
All feature creation begins with two-dimensional drawing in the
sketcher and then adding the third dimension in some way. The
sketcher has many menus to help create various types of
sketches.
The section of solid models must be closed without any loose
open ends and any overlapping with other curves. If there are
more than one outline, they must not intersect and all of them
must be closed.
Alternatively, the solid section can be made with open line
sketch and adding thickness by Thicken Sketch.
The section of surfaces (i.e., quilts) can be any way, open and
intersect.
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Sketch Window
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The Initial Orientation of Sketch Plane (SP)
In Creo, the initial orientation of the sketch plane and its reference planes
is in 3D.
You can use Sketch View command in Graphics Toolbar to get the sketch
view rather than 3D.
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Weak and Strong Dimensions
When a geometry is sketched, the default dimensions (so called, weak
dimensions) are given.
The dimension can be changed by double clicking it and entering a new
value > CR.
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Use Sketch View and then sketch with Line and Circle similar to below.
This shows default dimensions. Also, the sketch is shaded because the
sketch is closed (i.e., successful).
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1. Click and hold a dimension and move to a new position.
2. Double click a dimension and edit it and end it with CR. Repeat this for
all dimensions as shown below.
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To Create Dimensions
Click Dimension > select the entity or entities with the left mouse button >
place the dimension at the desired position using the middle mouse
button.
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Relations
Tools > Relation > enter the relation as shown below > Ok
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To Control the Dimensions
• Turn on/off the display in Graphics Toolbar.
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• To Modify the Number of Decimal Places in Dimensions, click
Parameters tab and change it (see below).
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To Replace a Dimension
• Replacing an existing
sketcher dimension with an
equivalent one that retains
the symbolic dimension
(sd#) of the original is useful
to preserve additional data
associated with the original
dimension (for example,
geometric tolerance symbol
or extra text added in
drawing mode). Click a
dimension > MRB > Replace
> create a new equivalent
dimension.
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In this example, the bottom horizontal dimension is to be replaced by another
new horizontal dimension.
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Negative Dimensions
For linear dimensions, you can enter a negative dimension value. This
causes the geometry to reverse direction. In Sketcher, the negative sign
always appears next to the dimension. In Part mode, dimension values
always appear as positive.
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Creating Geometry in Sketcher
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Tangent to Three Entities
Spline
Use Edge / Edge Offset
Coordinate System
Axis Point
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 Text
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Manipulating Sketcher Geometry
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Dragging
Dynamic Trim of Section Entities
Trim Entities to Each Other (Other Entities)
Divide Entities
Intersect Entities
Mirror Geometry
Dynamic Trimming and Possible Problems
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Dragging
Any geometry can be dragged to change the shape.
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To move a line, click select the line and then drag.
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Dynamic Trim of Section Entities
Edit > Trim > Delete Segment > click any segment to remove. When the
mouse is over a segment, it is highlighted ready to be selected.
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Trim Entities to Each Other (Other Entites)
Edit > Trim > Corner > click two entities (they do not have to intersect) on
the portion of the entity to keep
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Trim Entities by an Increment
Sketch > click Intent Manager (to turn off) > Geom Tools > Trim > Increm >
Enter the incremental length. A positive value lengthens an entity, and a
negative value shortens it. Note to use Untrim Last if needed
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Trim Entities to a Specific Length
Sketch > click Intent Manager (to turn off) > Geom Tools > Trim > Increm >
Enter the incremental length. A positive value lengthens an entity, and a
negative value shortens it. Note to use Untrim Last if needed
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Divide
Edit > Trim > Divide > Click the entity at the locations where you want to
divide.
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Intersect Entities
Sketch > click Intent Manager (to turn off) > Geom Tools > Intersect > pick
the first and second entities near the intersection point > Yes (to delete
dimensions). The entities are split at the intersection point
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Trim Entities to a Bounding Entity
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Mirror Geometry
Mirror Sketcher geometry about a sketched centerline. Select an entity or
multiple entities to mirror > click or Edit > Mirror > select a center line
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Dynamic Trimming and Possible Problems
First use [Extrude > Sketch > pick the top datum plane for sketch plane >
click Sketch button]. Now, in the sketcher, sketch the rough half section
and a horizontal line as shown. Don’t worry about the dimensions right
now. Note that a straight horizontal line is used to trim the arcs.
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Example 1
Create the following model by using various sketcher menus and
constraints.
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Tangent and Trim
 Extrude > …
 in the sketch mode draw circles and lines
 Constraint > Tangent
 Pick on one outer circle and then the line (make the line
tangent to circle)
 Repeat this for all tangent lines
 Constraint > Trim
 select entities to trim (i.e., delete)
Hole and Copy (see the website, Edit Feature > Copy, for details):
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Hole Dialog Window
ABOUT THREADS
For second linear reference, pick
on the axis of the big hole and
then HP to specify the distance
from the axis along HP.
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Example 2
Create the following model using the half sections in the sketcher.
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Sketch/Mirror and Tangent
 Extrude > Sketch the cylinder on HDP.
 For key hole, draw half the section in sketch mode and
use Mirror menu
Create center line
Draw lines
Change dimensions as needed
Select lines to mirror [shift key down and selecting
lines]
Click Mirror menu
Pick on center line for mirroring
 For protruded part to the
right, draw half the section
in sketch mode and use
Mirror menu
Create center line
Draw lines
Use constraint Tangent
to make the line tangent
to circle
Override default
dimensions and change
dimensions as needed
Select lines to mirror
[shift key down and
selecting lines]
Click Mirror menu
Pick on center line for
mirroring
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Dimension
Note that the angle dimension appearing in protruded part is not
active dimension, but reference dimension and must not be used to
define the shape.
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Example 3
Create the extended part that uses part of the outline of the existing part
on the right.
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Project
 Create the object on the right-side with a spline and lines
 Create two datum planes. First one at 30o angle to the front face of the
right-side object thru the vertical edge at front*. The second one is
created by offset from the previous at 60 distance
 Create > Solid > Protrusion > Extrude > One Side
 Select the second datum plane as sketch plane [do not flip arrow
direction**] and top datum as top plane
 Sketch > Project > Loop > select the front face of the object which is
defined by the loop (you may rotate the object for viewing. Now you see
projected sketch on the sketch plane)
 Draw a vertical line and Trim
 Sketch Done > Depth > Till Surface > select the front face of the original
object
* Thru > Select Edge > Angle > Select Plane > Done > enter value
** keep default direction because we use “UpTo Surface”.
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Hint: if you make a mistake in sketching and want to redo some parts,
then use “quit > cancel” and then click the item in dialog you want to
redo.
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Dimension
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Example 4
Create the part below by using Offset Edge.
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Offset Edge
Extrude > … > construct the bottom block with a round.
Extrude > One Side > select the top surface as SP > select the front
face as bottom RP > close refs window
Sketch > Edge Offset > Chain > select the first line and the last line to
offset clockwise (Arc can offset up to its radius).
Type in the value (can be negative) for offset
OK
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Dimension
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Working with Sections
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To Retrieve an Existing Section or Drawing
To Copy Imported Drawings into Sketcher
Edit > Copy
Edit > Scale and Rotate
To Exit Sketcher with an Incomplete Section
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Edit > Copy
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Edit > Scale and Rotate
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