2022.4+26187-e1209cf7 Apr 14, 2022

4 Geometry Operations

Cubit™ generally relies on the ACIS solid modeling kernel for geometry representation. Mesh-based geometry is also provided. Geometry is imported or created within Cubit. Geometry is created bottom-up or through primitives. Cubit imports ACIS SAT files. Cubit can also read STEP, IGES, and FASTQ files and convert them to the ACIS kernel. As of version 15.0, Cubit supports direct translators for Parasolid, SolidWorks, and Pro/Engineer for an additional license fee.

Once in Cubit, an ACIS model is modified through booleans. Without changing the geometric definition of the model, the topology of the model may be changed using virtual geometry. For example, virtual geometry can be used to composite two surfaces together, erasing the curve dividing them.

Sometimes, an ACIS model is poorly defined. This often happens with translated models. The model can be healed inside Cubit.

    4.1 Cubit Geometry Formats

      4.1.5 ACIS Geometry Kernel

      4.1.6 Mesh-Based Geometry

          4.1.6.2.1 Using tolerance on STL files

          4.1.6.2.2 Using the stitch option on AVS and facet files

          4.1.6.2.3 Using the improve option on facet files.

          4.1.6.2.4 Smoothing faceted surfaces.

          4.1.6.2.5 Creating a thin offset volume

          4.1.6.2.6 Creating volumes from surfaces

    4.2 Geometry Creation

      4.2.1 Bottom-Up Geometry Creation

        4.2.1.1 Creating Volumes

          4.2.1.1.1 Sweep Surface Along Vector

          4.2.1.1.2 Sweep Surface About Axis

          4.2.1.1.3 Sweep Surface Along Curve

          4.2.1.1.4 Sweep Surface Perpendicular

          4.2.1.1.5 Sweep Surface to a Volume

          4.2.1.1.6 Offset

          4.2.1.1.7 Sheet Extended from Surface

          4.2.1.1.8 Sweep Curve About Axis

          4.2.1.1.9 Stitch Surfaces Together

          4.2.1.1.10 Loft Surfaces Together

          4.2.1.1.11 Thicken Surfaces

          4.2.1.1.12 Sweeping a Surface to a Plane

          4.2.1.1.13 Sweep Surface along a Direction

          4.2.1.1.14 Sweep Surface along Helix

          4.2.1.1.15 Volume Copy

        4.2.1.2 Creating Curves

          4.2.1.2.1 Straight

          4.2.1.2.2 Parabolic, Circular, Ellipse

          4.2.1.2.3 Spline

          4.2.1.2.4 Example

          4.2.1.2.5 Copy

          4.2.1.2.6 Combine Existing Curves

          4.2.1.2.7 Arc Three

          4.2.1.2.8 Arc End Vertices and Radius

          4.2.1.2.9 Arc Center Vertex

          4.2.1.2.10 Arc Center Angle

          4.2.1.2.11 From Vertex Onto Curve

          4.2.1.2.12 Offset

          4.2.1.2.13 From Mesh Edge

          4.2.1.2.14 Close To

          4.2.1.2.15 Surface Intersection

          4.2.1.2.16 By Projection

          4.2.1.2.17 Creating a Helix

          4.2.1.2.18 Tangents

          4.2.1.2.19 Examples

        4.2.1.3 Creating Surfaces

          4.2.1.3.1 Bounding Curves

          4.2.1.3.2 Bounding Vertices or Nodes

          4.2.1.3.3 Copy

          4.2.1.3.4 Extended Surface

          4.2.1.3.5 Planar Surface

          4.2.1.3.6 Net Surface

          4.2.1.3.7 Offset

          4.2.1.3.8 Skinning

          4.2.1.3.9 Sweeping of Curves

          4.2.1.3.10 Midsurface

          4.2.1.3.11 Weld Profile

          4.2.1.3.12 Creating A Surface From Mesh Entities

          4.2.1.3.13 Creating a Circular Surface

          4.2.1.3.14 Creating a Parallelogram

          4.2.1.3.15 Creating an Ellipse

          4.2.1.3.16 Creating a Rectangle

        4.2.1.4 Creating Vertices

          4.2.1.4.1 XYZ location

          4.2.1.4.2 On Curve - Fraction

          4.2.1.4.3 On Curve - General

          4.2.1.4.4 From Vertex

          4.2.1.4.5 At Arc

          4.2.1.4.6 At Intersection

      4.2.2 Geometric Primitives

        4.2.2.2 Creating Bricks

        4.2.2.3 Creating Frustums/Cones

        4.2.2.4 Creating Pyramids

        4.2.2.5 Creating Toruses

        4.2.2.6 Creating Cylinders

        4.2.2.7 Creating Prisms

        4.2.2.8 Creating Spheres

    4.3 Geometry Transforms

      4.3.1 Align Command

      4.3.2 Copy Command

      4.3.3 Move Command

      4.3.4 Scale Command

      4.3.5 Rotate Command

      4.3.6 Reflect Command

    4.4 Geometry Booleans

      4.4.1 Intersect

      4.4.2 Subtract

      4.4.3 Unite

    4.5 Geometry Decomposition

      4.5.1 Splitting Geometry

        4.5.1.1 Split Curve

        4.5.1.2 Split Periodic Surfaces

        4.5.1.3 Split Surface

            4.5.1.3.3.1 Logical Rectangle

            4.5.1.3.3.2 Split Orientation

            4.5.1.3.3.3 Corner Specification

            4.5.1.3.3.4 Direction

            4.5.1.3.3.5 Segment|Fraction|Distance

            4.5.1.3.3.6 Through Vertex

            4.5.1.3.3.7 Parametric

            4.5.1.3.3.8 Tolerance

            4.5.1.3.3.9 Preview

            4.5.1.3.3.10 Settings

      4.5.2 Web Cutting

        4.5.2.2 Web Cutting with an Arbitrary Surface

        4.5.2.3 Chop Command

        4.5.2.4 Web Cutting with a Planar or Cylindrical Surface

        4.5.2.5 Web Cutting by Sweeping Curves or Surfaces

        4.5.2.6 Web Cutting using a Tool or Sheet Body

        4.5.2.7 Web Cutting Options

      4.5.3 Section Command

      4.5.4 Separating Surfaces from Bodies

      4.5.5 Separating Multi-Volume Bodies

    4.6 Geometry Cleanup and Defeaturing

      4.6.1 Automatic Geometry Clean-up

        4.6.1.1 Automatic Forced Sweepability

          4.6.1.1.1 Example

        4.6.1.2 Automatic Surface Split

          4.6.1.2.1 Example

        4.6.1.3 Automatic Small Curve Removal

        4.6.1.4 Automatic Small Surface Removal

          4.6.1.4.1 Example

      4.6.2 Healing

        4.6.2.1 Analyzing Geometry

        4.6.2.2 Auto Healing

        4.6.2.3 Healing Attributes

        4.6.2.4 Spline Removal

        4.6.2.5 What if Healing is Unsuccessful?

      4.6.3 Removing Geometric Features

        4.6.3.1 Removing Surfaces

        4.6.3.2 Removing Vertices

      4.6.4 Tweaking Geometry

        4.6.4.1 Tweaking Curves

        4.6.4.2 Tweak Remove Topology

        4.6.4.3 Tweaking Surfaces

            4.6.4.3.7.1 Hole Removal Example

            4.6.4.3.8.1 Fillet Removal Example

          4.6.4.3.9 Changing the Taper of Surfaces

        4.6.4.4 Tweaking Vertices

        4.6.4.5 Tweak Volume Bend

          4.6.4.5.1 Example

      4.6.5 Debugging Geometry

        4.6.5.1 Related Commands

      4.6.6 Finding Surface Overlap

          4.6.6.2.1 Facet - Absolute/Angle

          4.6.6.2.2 Gap - Minimum/Maximum

          4.6.6.2.3 Angle - Minimum/Maximum

          4.6.6.2.4 Normal

          4.6.6.2.5 Tolerance

          4.6.6.2.6 Group

          4.6.6.2.7 List

          4.6.6.2.8 Display

          4.6.6.2.9 Body

          4.6.6.2.10 Imprint

      4.6.7 Geometry Accuracy

      4.6.8 Regularizing Geometry

      4.6.9 Removing Blunt Tangencies

      4.6.10 Stitching Sheet Bodies

      4.6.11 Trimming and Extending Curves

      4.6.12 Validating Geometry

    4.7 Geometry Imprinting and Merging

      4.7.1 Examining Merged Entities

      4.7.2 Imprinting Geometry

      4.7.3 Merge Tolerance

      4.7.4 Merging Geometry

      4.7.5 Using Geometry Merging to Verify Geometry

      4.7.6 Unmerging

    4.8 Virtual Geometry

      4.8.1 Collapse Geometry

        4.8.1.1 Collapse Angle

          4.8.1.1.1 Simple

          4.8.1.1.2 Complete

        4.8.1.2 Collapse Curve

        4.8.1.3 Collapse Surface

      4.8.2 Composite Geometry

        4.8.2.1 Composite Curves

        4.8.2.2 Composite Surfaces

      4.8.3 Partitioned Geometry

        4.8.3.1 Partitioned Curves

        4.8.3.2 Partitioned Surfaces

        4.8.3.3 Partitioned Volumes

        4.8.3.4 Using Mesh Intersections to Partition Surfaces

        4.8.3.5 Removing Partitions

      4.8.4 Deleting Virtual Geometry

      4.8.5 Simplify Geometry

    4.9 Geometry Orientation

    4.10 Groups

      4.10.1 Basic Group Operations

      4.10.2 Groups in Graphics

      4.10.3 Group Propagation

      4.10.4 Propagated Groups

      4.10.5 Propagated Hex Groups

      4.10.6 Quality Groups

      4.10.7 Seeded Mesh Groups

    4.11 Geometry Attributes

      4.11.1 Entity IDs

      4.11.2 Entity Names

      4.11.3 Persistent Attributes

        4.11.3.1 Attribute Behavior

        4.11.3.2 Attribute Commands

        4.11.3.3 Attribute Types

        4.11.3.4 Using Cubit Attributes

    4.12 Entity Measurement

    4.13 Geometry Deletion

    4.14 Exporting Geometry

      4.14.1 Exporting ACIS Files

      4.14.2 Exporting Facet and STL Files

      4.14.3 Exporting IGES Files

      4.14.4 Exporting STEP Files

    4.15 Importing Geometry

      4.15.2 Importing ACIS Files

        4.15.2.1 Import Options

      4.15.3 Importing Facet Files

      4.15.4 Importing FASTQ Files

      4.15.5 Importing Granite Files

      4.15.6 Importing IGES Files

        4.15.6.1 Import Options

      4.15.7 Importing STEP Files

        4.15.7.1 Import Options

        4.15.7.2 Import Settings