Surface Continuity

Find

• G0 Positional Continuity – Only check for gaps between surfaces (labeled with “P” symbols).

• G1 Tangent Continuity – Check for gaps and tangent discontinuities (labeled with “T” symbols).

• G2 Curvature Continuity – Check for gaps, tangent, and curvature discontinuities (labeled with “C” symbols)

Check Spacing By

• Arc Length – Check the continuity at equally spaced points along the surface, determined by the Distance Between Checks option.

• Per Span – Check the continuity at a number of points in each span equal to the value of the Fitting > Curve Fit Checkpoints option of the Preferences > Construction Options window.

Distance Between Checks

The arc-length distance between continuity checks when using the Arc Length option.

This option only appears when Check Spacing By is Arc Length.

Display Options

Locator Persistence

If this option is checked on, the surface continuity indicators have the ability to become a persistent locator which updates with changes to the geometry.

Check Interior

If this option is checked on, continuity is checked and displayed along multiple-knot iso-parametric curves in the interior of the surface.

Show Max Labels

If this option is checked on, points of maximum positional, tangency angle and curvature deviation are shown. Note however that these labels only appear if part of the boundary has discontinuities (gaps, tangent or curvature breaks) that are out of tolerance.

Show Deviation

When checking positional continuity (G0 Positional Continuity), check this option to display a comb that shows positional deviation between two surfaces. You can use the to scale the comb and to edit the steps in the comb.

Show Edge Labels

If this option is checked on, indicators showing areas of discontinuities (“O”, “C” and “T” labels) are initially displayed along the boundaries. Red symbols indicate areas of maximum discontinuity. Blue symbols indicate areas of minimum discontinuity.

Show Comb

Check on this option to see the comb lines for gaps, tangency breaks, and curvature breaks.

Auto Scale

This option only appears if Show Combs is on. When Auto Scale is checked (default), the scale of the deviation combs is automatically calculated to be proportional to the size of the object.

When this option is unchecked, three Scale number fields appear (for Positional, Tangent, and Curvature deviation), allowing you to set the scales of the comb at the time of creation.

Scale

Three values (for Positional, Tangent, and Curvature deviation respectively) that allow you to adjust the scale of the combs at the time of creation. These values are only available if Auto Scale is turned off.

Use the Surface Continuity tool the to check the deviation and continuity along shared edges of surfaces. When check for positional continuity (G0) a deviation comb is also added.

Note: You can use the Pick > Locator tool to select the positional continuity locator and the deviation comb at the same time.

Use the Deviation > Angular Deviation tool to check for tangent continuity (G1) between surfaces, regardless of whether or not they have achieved positional continuity (G0).

Check the continuity between surfaces

1. Pick the surfaces you want to check by doing any of the following:

   • two connected edges.
   • select first edge and then Ctrl + the second edge.
   • Press Shift + , and then box select two edges. 

2. Select the Surface Continuity tool .

   The tool displays symbols along the shared edges representing the continuity and deviation at each sampling point.

   The calculation can take a long time for very complex models. To cancel the check, press .

   Tip: To get a complete review of the deviation and continuity set all options on: Locator Persistence, Show Max. Labels, Check interior, Show Edge Labels, Show Comb, and Show Deviation (for GO Positional Continuity only ).

3. Do any of the following:

   • Click an edge to add it to or remove it from the check. Hold and click a surface to add it or remove it.
   • Drag the on empty space to change the scale of any active deviation comb plots.
   • Drag the on empty space to change the sampling density.
   • -click an edge to switch it between deviation comb and symbol display.
   • Drag the along an edge to show detailed numeric information on the points under the mouse pointer.
   • Open the prompt line history window to see any messages the tool printed about continuity and deviation between the surfaces.

4. To switch between G0 Position Continuity, G1 Tangent Continuity, and G2 Curvature Continuity on multiple instances of the Surface Continuity locator, use the Position, Tangent, or Curvature buttons in the viewport to switch between continuity types, or use the spacebar to cycle through them.

   Note: If you switch to either G1 Tangent or G2 Curvature continuity before G0 continuity is met, the G0 locator persists along with the deviation comb to indicate the continuity failure.

How do I read the symbolic display?

Line style	Meaning
Pale green, dotted.	Edge with no adjacent surface, or an adjacent surface that is not selected. Hold and click a surface to select it.
Bright green	Selected isoparametric curve with achieved continuity.
Dark green	Isoparametric curve with achieved continuity.
Yellow	Selected isoparametric curve with continuity break.
Red	Isoparametric curve with continuity break.

These colors may be different if you have changed the interface color preferences.

What if...?

I want the comb plots on all the surfaces to use the same scale

1. Shift-select the Continuity > Surface Continuity tool .
2. Turn on Show Combs, and turn off Auto Scale.
3. Enter the scale factors for Positional, Tangent, and Curvature deviation combs respectively in the three Scale fields.

I want to change the tolerances?

Choose Preferences > Construction Options and open the Tolerances and Continuity sections.

The calculation takes too long?

1. Shift-select the Continuity > Surface Continuity tool .
2. Increase the Distance Between Checks setting to make the tool calculate fewer sample points.