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

 Using tolerance on STL files

 Using the stitch option on AVS and facet files

 Using the improve option on facet files.

 Smoothing faceted surfaces.

 Creating a thin offset volume

 Creating volumes from surfaces

    4.2 Geometry Creation

      4.2.1 Bottom-Up Geometry Creation Creating Volumes

 Sweep Surface Along Vector

 Sweep Surface About Axis

 Sweep Surface Along Curve

 Sweep Surface Perpendicular

 Sweep Surface to a Volume


 Sheet Extended from Surface

 Sweep Curve About Axis

 Stitch Surfaces Together

 Loft Surfaces Together

 Thicken Surfaces

 Sweeping a Surface to a Plane

 Sweep Surface along a Direction

 Sweep Surface along Helix

 Volume Copy Creating Curves


 Parabolic, Circular, Ellipse




 Combine Existing Curves

 Arc Three

 Arc End Vertices and Radius

 Arc Center Vertex

 Arc Center Angle

 From Vertex Onto Curve


 From Mesh Edge

 Close To

 Surface Intersection

 By Projection

 Creating a Helix


 Examples Creating Surfaces

 Bounding Curves

 Bounding Vertices or Nodes


 Extended Surface

 Planar Surface

 Net Surface



 Sweeping of Curves


 Weld Profile

 Creating A Surface From Mesh Entities

 Creating a Circular Surface

 Creating a Parallelogram

 Creating an Ellipse

 Creating a Rectangle Creating Vertices

 XYZ location

 On Curve - Fraction

 On Curve - General

 From Vertex

 At Arc

 At Intersection

      4.2.2 Geometric Primitives Creating Bricks Creating Frustums/Cones Creating Pyramids Creating Toruses Creating Cylinders Creating Prisms 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 Split Curve Split Periodic Surfaces Split Surface

   Logical Rectangle

   Split Orientation

   Corner Specification



   Through Vertex





      4.5.2 Web Cutting Web Cutting with an Arbitrary Surface Chop Command Web Cutting with a Planar or Cylindrical Surface Web Cutting by Sweeping Curves or Surfaces Web Cutting using a Tool or Sheet Body

 Webcut with Existing Tool Body

 Webcut with Curve Loop

 Webcut with Offset Surfaces 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 Automatic Forced Sweepability

 Example Automatic Surface Split

 Example Automatic Small Curve Removal Automatic Small Surface Removal


      4.6.2 Healing Analyzing Geometry Auto Healing Healing Attributes Spline Removal What if Healing is Unsuccessful?

      4.6.3 Removing Geometric Features Removing Surfaces Removing Vertices

      4.6.4 Tweaking Geometry Tweaking Curves Tweak Remove Topology Tweaking Surfaces

   Hole Removal Example

   Fillet Removal Example

 Changing the Taper of Surfaces Tweaking Vertices Tweak Volume Bend


      4.6.5 Debugging Geometry Related Commands

      4.6.6 Finding Surface Overlap

 Facet - Absolute/Angle

 Gap - Minimum/Maximum

 Angle - Minimum/Maximum








      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 Collapse Angle


 Complete Collapse Curve Collapse Surface

      4.8.2 Composite Geometry Composite Curves Composite Surfaces

      4.8.3 Partitioned Geometry Partitioned Curves Partitioned Surfaces Partitioned Volumes Using Mesh Intersections to Partition Surfaces 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 Attribute Behavior Attribute Commands Attribute Types 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 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 Import Options

      4.15.7 Importing STEP Files Import Options Import Settings