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Geometric dimensioning and tolerancing

TechDraw

Introduction

The preferences for the TechDraw Workbench can be found in the Preferences Editor. In the menu select Edit → Preferences and then TechDraw. This group is only available if the TechDraw Workbench has been loaded in the current FreeCAD session.

There are seven pages: General, Scale, Dimensions, Annotation, Colors, HLR and Advanced.

All preferences with italic labels are default values for new drawing objects. They have no effect on existing objects.

General

Drawing Update

• Update with 3D (global policy): Whether or not pages are updated every time the 3D model is changed.
• Allow page override (global policy): Whether or not a page's Keep Updated property can override the global Update with 3D parameter.
• Keep page up to date: Keeps drawing pages in sync with changes of the 3D model in real time. This can slow down the response time.
• Auto-distribute secondary views: Automatically distributes secondary views for projection groups.

Labels

• Label font: The name of the font for labels. The font is also used for new dimensions, changing it has no effect on existing dimensions.
• Label size: Default size for labels.

Conventions

• Projection group angle: If projection groups will use either first-angle (European) projection or third-angle (American) projection. See multiview projection for an explanation.
• Section line convention: Standard for section lines that controls the position of arrows and symbol (introduced in 1.0). The options are:
  • ANSI
  • ISO

Files

• Default template: Default template file for new pages.
• Template directory: Starting directory for toolbar button New Page From Template.
• Hatch pattern file: Default SVG or bitmap file for hatches.
• Line group file: Alternate file for personal line group definitions.
• Welding directory: Default directory for toolbar button Weld Symbol.
• PAT file: Default PAT pattern definition file for geometric hatches.
• Pattern name: Name of the default PAT pattern.
• Symbol directory: Alternate directory to search for SVG symbol files.

Grid

• Show grid: Default Show Grid setting for new pages.
• Grid spacing: Default distance between grid lines for new pages.

Selection

• Enable multi-selection mode: If enabled, clicking without Ctrl does not clear the existing selection. introduced in 1.0

View Defaults

• View frames mode : Controls when the view boundary frames and labels are displayed. introduced in 1.2
  • Auto: Show on hover,
  • On: Always show,
  • Off: Never show.
• Use 3D camera direction: If checked, the 3D camera direction (or normal of a selected face) will be used as the view direction. If not checked, Views will be created as Front Views. introduced in 1.0
• Always show label: If checked, view labels will be displayed even when frames are suppressed. introduced in 1.0

Snapping

• Snap view alignment: If checked, Views will be snapped into alignment when dragged. introduced in 1.0
• View snapping factor: Tolerance for snapping of Views - if a View is within this fraction of View size of perfect alignment, it will snap into alignment. introduced in 1.0
• Snap detail highlights: If checked, detail view highlights will be snapped to the nearest vertex when dragging in TaskDetail. introduced in 1.1
• Highlight snapping factor: Snap radius for highlights. Vertex must be within this factor times the highlight size to be a snap target. introduced in 1.1

Scale

Scale

• Page scale: Default scale for new pages.
• View scale type: Default scale for new views.
• View custom scale: Default scale for views if View scale type is Custom.
• Legacy symbol scaling: Uses the original (incorrect) scaling method for SVG symbols, Spreadsheet views and Draft views as used in v1.0 and earlier. Otherwise, a more accurate method will be used.

Size Adjustments

• Vertex scale: Scale of vertex dots. Multiplier of line width.
• Center mark scale: Size of center marks. Multiplier of vertex size.
• Template edit mark: Size of template field click handles in mm (green dots).
• Welding symbol scale: Multiplier for size of welding symbols.

Dimensions

Dimensions

• Standard and style: The standard to be used for dimensional values. The differences between the standards are shown in the image:

  

ISO oriented - drawn according to the standard ISO 129-1, text is rotated to be parallel with the dimension line tangent.

ISO referencing - drawn in compliance with ISO 129-1, text is always horizontal, above the shortest possible reference line.

ASME inlined - drawn according to the standard ASME Y14.5M, text is horizontal, inserted in a break within the dimension line or arc.

ASME referencing - drawn in compliance with ASME Y14.5M, text is horizontal, short reference line is attached to one side's vertical center.

• Use global decimals: Use number of decimals from the general preferences.
• Show units: Appends the unit (mm, in, etc.) to dimension values.
• Alternate decimals: Number of decimals if Use Global Decimals is not selected and Dimension Format not specified.
• Dimension format: Custom format for dimension text. Uses the printf format specifier.
• Font size: Font size for dimension text.
• Tolerance text scale: Tolerance font size adjustment. Multiplier of dimension Font Size.
• Diameter symbol: Character used to indicate diameter dimensions.
• Arrow style: Arrowhead style for dimensions.
• Arrow size: Arrowhead size of dimensions.
• Extension gap factor - ISO: Gap between dimension point and start of extension lines for ISO dimensions. introduced in 0.21
• Extension gap factor - ASME: Gap between dimension point and start of extension lines for ASME dimensions. introduced in 0.21
• Line spacing - ISO: Spacing between the dimension line and dimension text for ISO dimensions. introduced in 0.21

Tools

• Dimensioning tools: Select the type of dimensioning tools for the toolbar. Whichever you choose, all tools are always available in the menu and through shortcuts. The options are: introduced in 1.0
  • Single tool: A single tool for all dimensioning in the toolbar: Distance, Distance X / Y, Angle, Radius. Others in dropdown.
  • Separated tools: Individual tools for each dimensioning tool.
  • Both: You will have both the 'Single tool' and the separated tools.
• Dimension tool diameter/radius mode: While using the Dimension tool you may choose how to handle circles and arcs: introduced in 1.0
  • Auto: The tool will apply radius to arcs and diameter to circles.
  • Diameter: The tool will apply diameter to all.
  • Radius: The tool will apply radius to all.

Annotation

Annotation

• Section cut surface: Style for section cut surface. The options are:
  • Hide: There is no visible surface.
  • Solid color: The surface gets the color set for Section Face
  • SVG hatch: The surface is hatched.
  • PAT hatch: The surface is geometrically hatched.
• Show section line in source view: If checked, the section annotation will be drawn on the Source view. If unchecked, no section line, arrows or symbol will be shown in the Source view. introduced in 1.0
• Include cut line in section annotation: If checked, the cut line will be drawn on the Source view. If unchecked, only the change marks, arrows and symbols will be displayed. introduced in 1.0
• Complex section line marks: Show marks at direction changes on ComplexSection lines. introduced in 0.21
• Detail view outline shape: Outline shape for detail views. The options are:
  • Circle
  • Square
• Detail view show matting: This checkbox controls whether or not to display the outline around a detail view. introduced in 1.0
• Detail source show highlight: This checkbox controls whether or not to display a highlight around the detail area in the detail's source view. introduced in 1.0
• Balloon shape: Shape of balloon annotations.
• Balloon leader end: Default style for balloon leader line ends, see balloon properties.
• Balloon leader kink length: Length of balloon leader line kink.
• Balloon orthogonal triangle: If Balloon Leader end is Filled triangle, the triangle can only get a vertical or horizontal direction when the balloon is moved.
• Leader line auto horizontal: Forces last leader line segment to be horizontal.
• Broken view break type: Default break type used to indicate BrokenViews: introduced in 1.0
  • No break lines
  • Zigzag lines
  • Simple lines
• Show center marks: Show arc center marks in views.
• Print center marks: Show arc centers in printed output.
• Enforce ISO 8601 date format: Fills out template date fields using ccyy-mm-dd format automatically, even if that is not the standard format for the current locale.

Lines

• Line standard: Standard to be used to draw section lines in section views.
• Line width group: A LineGroup to set the default line widths.
• Hidden line style: Style of hidden lines. introduced in 1.0
• Section line style: Style for section lines.
• Detail highlight style: Line style of the outline shape for detail views.
• Center line style: Default style for centerlines.
• Break line style: Default style for lines used to indicate BrokenViews. introduced in 1.0
• Line end cap shape: The default (round) should almost always be the right choice. Flat or square caps are useful if you are planning to use a drawing as a 1:1 cutting guide.

Colors

Setup of the default colors for new pages:

• Normal: Normal line color.
• Preselected: Preselection color. The color that is used to highlight objects when hovering with the mouse over them.
• Selected: Color for selected objects.
• Background: Background color around pages.
• Dimension: Color of dimension lines and text.
• Centerline: Color for centerlines.
• Detail highlight: Line color for the outline shape of detail views.
• Grid color: Color for all page grids.
• Template underline: Color for the underline that marks editable texts in templates. introduced in 1.0
• Hidden line: Hidden line color. This color will be used for all kinds of hidden lines.
• Section face: Color of the section view cut surface. Only used if the setting Section cut surface is set to Solid Color.
• Section line: Color of the section view cut line.
• Hatch: Hatch image color.
• Geometric hatch: Geometric hatch pattern color.
• Vertex: Color of the selectable vertices in views.
• Leader line: Color for new leaderlines.
• Transparent faces: If checked, object faces will be transparent. Otherwise the set color will be used for faces.
• Light on dark: If checked text and lines will have a light color. To be used if the Page color is dark. Transparent or light colored faces are recommended with this option. introduced in 0.21
• Monochrome: If checked, the set color will be used for all text and lines. introduced in 0.21
• Page color: The background color of the page. introduced in 0.21

HLR

HLR stands for hidden line removal.

• Use polygon approximation: Uses an approximation to find hidden lines. This is fast, but the result is a collection of short straight lines.
• Show hard lines: Shows hard and outline edges (visible lines always shown)
• Show smooth lines: Shows smooth lines. A smooth line is a line indicating a change between tangent surfaces, as in the transition from a flat surface to a fillet.
• Show seam lines: Show seam lines. A seam line is a boundary between faces.
• Show UV ISO lines: Shows ISO lines. ISO stands for isoparametric. Here is a description what isoparametric lines (in fact curves) are.
• ISO count: The number of ISO lines per face edge.

Advanced

• Detect faces: If checked, TechDraw will attempt to build faces using the line segments returned by the hidden line removal algorithm. Faces must be detected in order to use hatching, but there can be a performance penalty in complex models.
• Report progress: Issue progress messages while building View geometry. introduced in 0.21
• Use new face finder algorithm: If checked, the new face finder algorithm will be used instead of the original one. introduced in 0.21
• Auto-correct dimension references: If checked, an attempt is made to update dimension references when the model changes. introduced in 0.21
• Show section edges: Highlights the border of the section cut in section views.
• Fuse before section: Performs a fuse operation on the input shape(s) before Section view processing.
• Switch workbench on click: If checked, double-clicking on a page in the tree will automatically switch to TechDraw and the page will be made visible. introduced in 1.1
• Allow crazy edges: Includes edges with unexpected geometry in results, e.g. zero lengths.
• Validate shapes: If checked, input shapes will be checked for errors before use and invalid shapes will be skipped. It can be slower but may prevent crashes. introduced in 1.1
• Debug section: Dumps intermediate results during a Section view processing.
• Debug bad shape: If checked, shapes that failed validation will be saved as B-rep files for later analysis. introduced in 1.1
• Debug detail: Dumps intermediate results during a Detail view processing.
• Overlap edges scrub passes: The number of attempts to remove overlapping edges returned by the Hidden Line Removal algorithm. A value of 0 indicates no scrubbing. Values above 2 are generally not productive. Each attempt adds to the time required to produce the drawing. introduced in 0.21
• Edge fuzz: Size of selection area around edges. The fuzz unit is approximately 0.1 mm, depending on your current zoom. The default is 10. Values in the 20-30 range will make it noticeably easier to select edges. Large numbers will cause overlaps with other drawing elements.
• Mark Fuzz: Selection area around center marks. The fuzz unit is approximately 0.1 mm, depending on your current zoom.
• Max SVG hatch tiles: The limit of SVG tiles with a size of 64x64 pixels used to hatch a single face. For large scalings one might get an error about to many SVG tiles, then one needs to increase the tile limit.
• Maximum PAT hatch segments: The maximum hatch line segments used when hatching a face with a PAT pattern.
• Balloon drag: Modifier key for balloon drag can be changed from the default here to avoid conflicts with OS or navigation style key bindings. introduced in 1.0

Geometric dimensioning and tolerancing

TechDraw