Sketcher External: Difference between revisions

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{{Docnav|[[Sketcher_Extend|Extend]]|[[Sketcher_CarbonCopy|CarbonCopy]]|[[Sketcher_Workbench|Sketcher]]|IconL=Sketcher_Extend.svg|IconC=Workbench_Sketcher.svg|IconR=Sketcher_CarbonCopy.svg}}

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{{GuiCommand
{{GuiCommand|Name=Sketcher External|Workbenches=[[Sketcher Workbench|Sketcher]], [[PartDesign Workbench|PartDesign]]|Shortcut=E|MenuLocation=Sketch → Sketcher geometries → Sketcher External|SeeAlso=[[Sketcher_ConstructionMode|ConstructionMode]]}}
|Name=Sketcher External
|Workbenches=[[Sketcher Workbench|Sketcher]]
|Shortcut=X|MenuLocation=Sketch → Sketcher geometries → Sketcher External
|SeeAlso=[[Sketcher_ToggleConstruction|ConstructionMode]]
}}


==Description== <!--T:2-->
==Description== <!--T:2-->


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When a sketch is mapped to a face of a solid, the Sketcher External Geometry tool can be used to link to an edge or vertex of that solid. It works by inserting a linked construction geometry into the sketch. The default colour of externally linked edges, is magenta. As with standard non-linked construction geometry (blue), the externally linked geometry is only visible when the sketch is in edit mode and is not directly used in the subsequent result, from use of the sketch in another tool. Both types of construction geometry are used as a reference for constraints, within the sketch.
Use the '''Sketcher External Geometry''' tool when you need to apply a constraint between sketch geometry and something outside of the sketch. It works by inserting a linked construction geometry into the sketch. The default colour of externally linked edges is magenta. As with standard non-linked construction geometry (blue), the externally linked geometry is only visible when the sketch is in edit mode and is not directly used in the subsequent result from use of the sketch in another tool. Both types of construction geometry may be used as a reference for constraints within the sketch.


A note of caution, using this tool to link to generated (solid) geometry can lead to unexpected results due to [[Topological_naming_problem|Topological Naming Problem]]. Also see [[Feature_editing#Advice_for_creating_stable_models|Advice for stable models]].


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[[FILE:Sketcher_ExternalEsempio1.png]]
This tool is used constrain elements of a sketch with reference to an element of an external solid, to which the sketch has been mapped. For example, it could be used to pocket a hole in the centre of a solid or 30mm from one end etc..
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==Usage== <!--T:8-->
The external geometry tool can only be applied to edges and/or vertices of the solid to which the sketch has been mapped. Consequently you can only link to elements of 3d solids. The edges may be straight, an arc or a circle.


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* Create a new sketch, or open an existing sketch.
You can not link to an external geometry of the solid which will be created from the sketch you are currently editing. This seems logical, however is a common issue when re-editing a sketch. When re-editing a sketch of a PartDesign feature which is mapped to the face of a solid (e.g. if you want to go back and change a sketch for a Pad002 where that sketch was mapped to a face of another Pad001) it is necessary to hide the solid the currently being edited sketch created (Pad002) and un-hide the previous solid (Pad001), so that you can see the previous solid (Pad001) if you wish to be able to apply the external geometry tool to one of its elements.
* Click 'Sketcher External' button
* Select an edge or a vertex that you want to link to in the sketch.
* Press Esc, or select another tool to stop importing geometry into the sketch.


=== Selection rules === <!--T:30-->
Selection rules for what objects can be imported differ drastically between FC v0.16 and FC v0.17.


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==== v0.17 And later ==== <!--T:31-->
* Only edges and vertices from objects from same coordinate system are allowed.
[[FILE:Sketcher_ExternalEsempio1.png]]


==Use== <!--T:8-->
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That is, the sketch and the object must be in same Body (when in part design WB), or in same Part (when in part WB), or both outside of any Parts and Bodies.
* Create a new sketch on face of a solid (Click on the solid face, then click the create sketch button) or map an existing sketch to a selected face of a solid (first select a single face of a solid then use the "Map Sketch to Face" tool).
* Click the 'Sketcher External' button
* Select the edge, or vertex, of the solid that you want to link to in the sketch (remember this must be an edge or vertex of the solid to which the sketch is mapped)


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For example, If the open sketch is in Body, you can use another sketch from Body as external geometry, but you can't use a sketch from Body001, or an edge from a Part Cube in the root of the project. Use Shapebinder feature to bring in a copy of the object into the coordinate system of open sketch. Then you will be able to use edges/vertices of Shapebinder object.

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* No circular dependencies are allowed.

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That means, you can't link to Pocket made with this sketch. You can't link to any object that depends on the sketch.

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Unlike in v0.16, sketch doesn't have to be on any face in order to use this tool. Links directly between sketches are possible, and encouraged, as they are more reliable.

==== v0.16 and older ==== <!--T:37-->
* You can only link to edges/vertices of the shape the sketch is mapped to.

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For example. If Sketch was made on a face of Pad, you can only use edges/vertices of Pad. You can't use edges of Sketch that was used to make Pad. You can't use edges of Pad that are inherited onto a Pocket done with this sketch (you need to hide Pocket and unhide Pad to link new stuff in).

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The sketch MUST be mapped to a face in order to use this tool.


===Appearance When Successfully Linked === <!--T:15-->
===Appearance When Successfully Linked === <!--T:15-->
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===Similarity to Construction Lines=== <!--T:16-->
===Similarity to Construction Lines=== <!--T:16-->
External geometry (default colour magenta) lines are similar (default colour blue) [[Sketcher_ConstructionMode|Contruction lines]] except in that the external geometry magenta lines are parametrically linked back to an element of the solid to which the sketch is mapped.
External geometry (default colour magenta) lines are similar (default colour blue) [[Sketcher_ToggleConstruction|Contruction lines]] except in that the external geometry magenta lines are parametrically linked back to an element of the solid to which the sketch is mapped.
Construction geometry are lines that are internal to the sketch, are only visible when the sketch is in edit mode and will be used for constraint references only, and not directly for later solid operations, like Pad or Pocket.
Construction geometry are lines that are internal to the sketch, are only visible when the sketch is in edit mode and will be used for constraint references only, and not directly for later solid operations, like Pad or Pocket.



===Use Of External Geometry in a PartDesign Workbench Work Flow=== <!--T:18-->
===Use Of External Geometry in a PartDesign Workbench Work Flow=== <!--T:18-->
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The external Geometry tool can, for example, be used as a reference for a constraint being used to position a hole in an object, at a specific location.
The external geometry can, for example, be used as a reference for a constraint being used to position a hole in an object at a specific location relative to an edge or vertex.


===Use Of External Geometry in a Part Workbench Work Flow=== <!--T:24-->
===Use Of External Geometry in a Part Workbench Work Flow=== <!--T:24-->
Part Workbench tools make new separate solids, unlike PartDesign tools which make a new feature of a single solid.


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You can use any Part geometry that is in coordinate system of the sketch. It is advised to link to the earliest feature possible, as it forms a more stable link.
Some of the Part workbench tools can use a sketch for input. Where this is the case, the sketch can use the External geometry tool if the sketch is mapped to a face of a solid in a similar way to the PartDesign workbench.


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In v0.16 and older, the sketch must be mapped to a face to use this tool. Since v0.17, this limitation was lifted.
Unlike a PartDesign tool, the result of a Part tool will be a separate solid and the placement parameters can be modified after construction. The sketch will define the location of the solid constructed from it, when its placement parameters are set to zero. Any changes made to these placement values will move the solid relative to the location defined by the sketch.


==Example== <!--T:11-->
==Example== <!--T:11-->
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In this case they are used as a reference for tangency constraints with the circumferences of one circle. They are also used as the reference for a horizontal and a vertical constraint to locate the centre of the second circle relative to the end and top of the Pad.
In this case they are used as a reference for tangency constraints with the circumferences of one circle. They are also used as the reference for a horizontal and a vertical constraint to locate the centre of the second circle relative to the end and top of the Pad.
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[[FILE:Sketcher_ExternalEsempio2.png]]
[[FILE:Sketcher_ExternalEsempio2.png]]
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This is the same sketch in edit mode, with the Pad upon which it is mapped hidden.
This is the same sketch in edit mode, with the Pad upon which it is mapped hidden.


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[[FILE:Sketcher_ExternalEsempio4.png]]
[[FILE:Sketcher_ExternalEsempio4.png]]
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When the sketch edit mode is closed, External Geometry lines are not visible.
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When the sketch edit mode is closed, external Geometry lines are not visible.

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[[FILE:Sketcher_ExternalEsempio3.png]]
[[FILE:Sketcher_ExternalEsempio3.png]]
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Revision as of 13:21, 29 October 2020

Sketcher External

Menu location
Sketch → Sketcher geometries → Sketcher External
Workbenches
Sketcher
Default shortcut
X
Introduced in version
-
See also
ConstructionMode

Description

Use the Sketcher External Geometry tool when you need to apply a constraint between sketch geometry and something outside of the sketch. It works by inserting a linked construction geometry into the sketch. The default colour of externally linked edges is magenta. As with standard non-linked construction geometry (blue), the externally linked geometry is only visible when the sketch is in edit mode and is not directly used in the subsequent result from use of the sketch in another tool. Both types of construction geometry may be used as a reference for constraints within the sketch.

A note of caution, using this tool to link to generated (solid) geometry can lead to unexpected results due to Topological Naming Problem. Also see Advice for stable models.

Usage

  • Create a new sketch, or open an existing sketch.
  • Click 'Sketcher External' button
  • Select an edge or a vertex that you want to link to in the sketch.
  • Press Esc, or select another tool to stop importing geometry into the sketch.

Selection rules

Selection rules for what objects can be imported differ drastically between FC v0.16 and FC v0.17.

v0.17 And later

  • Only edges and vertices from objects from same coordinate system are allowed.

That is, the sketch and the object must be in same Body (when in part design WB), or in same Part (when in part WB), or both outside of any Parts and Bodies.

For example, If the open sketch is in Body, you can use another sketch from Body as external geometry, but you can't use a sketch from Body001, or an edge from a Part Cube in the root of the project. Use Shapebinder feature to bring in a copy of the object into the coordinate system of open sketch. Then you will be able to use edges/vertices of Shapebinder object.

  • No circular dependencies are allowed.

That means, you can't link to Pocket made with this sketch. You can't link to any object that depends on the sketch.

Unlike in v0.16, sketch doesn't have to be on any face in order to use this tool. Links directly between sketches are possible, and encouraged, as they are more reliable.

v0.16 and older

  • You can only link to edges/vertices of the shape the sketch is mapped to.

For example. If Sketch was made on a face of Pad, you can only use edges/vertices of Pad. You can't use edges of Sketch that was used to make Pad. You can't use edges of Pad that are inherited onto a Pocket done with this sketch (you need to hide Pocket and unhide Pad to link new stuff in).

The sketch MUST be mapped to a face in order to use this tool.

Appearance When Successfully Linked

A (default magenta) coloured line will be overlaid when an edge is successfully linked (the vertices will be red), and will be visible in your sketch only while your sketch is in edit mode.

Similarity to Construction Lines

External geometry (default colour magenta) lines are similar (default colour blue) Contruction lines except in that the external geometry magenta lines are parametrically linked back to an element of the solid to which the sketch is mapped. Construction geometry are lines that are internal to the sketch, are only visible when the sketch is in edit mode and will be used for constraint references only, and not directly for later solid operations, like Pad or Pocket.

Use Of External Geometry in a PartDesign Workbench Work Flow

In the PartDesign workbench work flow, the External Geometry tool is used to assist in the positioning of an aspect of the solid you are constructing, relative to the previous stage in its construction. PartDesign workbench is intended to produce one single solid, therefore these sketches with external geometry are used to create a new feature of that one single solid.

The external geometry can, for example, be used as a reference for a constraint being used to position a hole in an object at a specific location relative to an edge or vertex.

Use Of External Geometry in a Part Workbench Work Flow

You can use any Part geometry that is in coordinate system of the sketch. It is advised to link to the earliest feature possible, as it forms a more stable link.

In v0.16 and older, the sketch must be mapped to a face to use this tool. Since v0.17, this limitation was lifted.

Example

This, below, is a sketch mapped to the top face of a solid created from a Pad of a previous sketch. The magenta lines are External Geometry linked to two edges of this pre-existing Pad.

In this case they are used as a reference for tangency constraints with the circumferences of one circle. They are also used as the reference for a horizontal and a vertical constraint to locate the centre of the second circle relative to the end and top of the Pad.

This is the same sketch in edit mode, with the Pad upon which it is mapped hidden.

When the sketch edit mode is closed, external Geometry lines are not visible.