More Constraints Than Houdini

Transcription

1 11/30/2005-8:00 am - 9:30 am Room:Swan 1 (Swan) Walt Disney World Swan and Dolphin Resort Orlando, Florida More Constraints Than Houdini Thomas Short, P.E. - Munro & Associates, Inc. and Anthony Dudek MA31-3 Knowledge of constraints in Inventor is the key to escaping the bonds of time-consuming part and assembly creation. Join these master AU instructors for a detailed expose of the secrets of the part, assembly, and motion constraints in Autodesk Inventor. Review their features and see neat applications with tips and tricks that Houdini himself would have been proud of. This session will benefit anyone who is confused by the use of constraint-based technology to capture design intent. Many users try to achieve the same functionality via dimensions, workarounds, etc. About the Speaker: Tom is a mechanical engineer registered as a professional in Michigan. He has taught and consulted on AutoCAD, Autodesk Inventor, and Autodesk Mechanical Desktop for many years in the U.S. and other countries. At Munro & Associates, Inc., Tom is a consultant on Lean Design, and has worked with a variety of companies helping them improve their designs for simplicity and ease of assembly. He is also an author with books on Inventor and Mechanical Desktop. Tom has presented at every Autodesk University since its inception 12 years ago. One of Tony's main ideas overarching his 20-year-long career in engineering is that designing in 3D is a smarter and faster way to work. His philosophy is "Whatever it takes, do it right the first time." Tools like Autodesk Inventor can help achieve that goal. He believes that the engineering landscape in America has changed from an internal, ownership environment to an overextended and outsourced managed environment. Within this context, we are challenged to continue to deliver more quality in less time. This is the challenge of our generation of technology workers. The future is very promising with new technologies and methods being implemented every day. This will be Tony's 11th year at Autodesk University. dudea1@bp.com

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3 November 28 December 1, 2005 Orlando, Florida More Constraints than Houdini Thomas Short & Anthony Dudek MA31-3 Knowledge of constraints in Inventor is the key to escaping the bonds of time-consuming part and assembly creation. Join these master AU instructors for a detailed expose of the secrets of the part, assembly, and motion constraints in Autodesk Inventor. Review their features and see neat applications with tips and tricks that Houdini himself would have been proud of. This session will benefit anyone who is confused by the use of constraint-based technology to capture design intent. Many users try to achieve the same functionality via dimensions, workarounds, etc. About the Speakers: One of Tony's main ideas overarching his 20-year-long career in engineering is that designing in 3D is a smarter and faster way to work. His philosophy is "Whatever it takes, do it right the first time." Tools like Autodesk Inventor can help achieve that goal. He believes that the engineering landscape in America has changed from an internal, ownership environment to an overextended and outsourced managed environment. Within this context, we are challenged to continue to deliver more quality in less time. This is the challenge of our generation of technology workers. The future is very promising with new technologies and methods being implemented every day. This will be Tony's 11th year at Autodesk University. Tom is a mechanical engineer registered as a professional in Michigan. He has taught and consulted on AutoCAD, Autodesk Inventor, and Autodesk Mechanical Desktop for many years in the U.S. and other countries. At Munro & Associates, Inc., Tom is a consultant on Lean Design, and has worked with a variety of companies helping them improve their designs for simplicity and ease of assembly. He is also an author with books on Inventor and Mechanical Desktop. Tom has presented at every Autodesk University since its inception 12 years ago. Objectives To review the control and use of the eleven 2D geometric constraints and the seven (1/2) 3D constraints in: Inventor Release 10 We will demonstrate most of these and review some of the lesser known features and their applications. 2D Geometric Constraints These are used on Profiles to geometrically relate the objects; the lines, arcs, and circles. Some are applied as you create the sketch and some you add to buildin your own geometric relationships. Our eventual goal in most parts is to have fully constrained sketches and that results in more robust parts and assemblies. Applying constraints reduces the number of dimensions required to fully constrain the sketch. 1

4 2D Constraints The constraints on a sketch can be displayed by: 1. Selecting display constraints from the sketch panel and picking an object. 2. Or select Display All Constraints from the right mouse menu. 3. Constraints are displayed as symbols on the objects. The size of the symbol cannot be changed. The relationship between symbols can be displayed by hovering over the symbol Objects and features you can select for constraints: lines, part edges, and projected features including work objects and their end points and mid-points Arcs and arc features and their end points and center points Circles and circular features and their center points Examples: 1. The midpoint coincident trick. 2. Vertical & Horizontal vs. Construction Geometry 3. Using projected work planes. 4. Using the Symmetric constraint. Symbol & Name Works On No. of Picks Function 1st Choice, Object to Change 2nd Choice, Object to Reference Special Line & Splines 2 Makes Line perpendicular to 2nd choice object Line or spline LLAN, Line or Spline For splines, end points must be coincident Line 2 Makes Line parallel to 2nd choice object Line LLAN or Line Both objects can't Line, Arc, Circle, or end points of Splines 2 Forces 1st object to be Line, Arc, Circle, tangent to 2nd or Spline LLAN, Line, Arc, be Lines. For Circle, or Spline splines, end points must be coincident Any Point (mid, end, Makes two points For point to line, center, spline point) 2 coincident or a point Any Point Point or Line the point can still and Lines coincident with a line slide along line Arc or Circle (includes Ellipse) 2 Forces two objects to have the same center. Arc or Circle Arc or Circle Coincident for center pints has the same effect Line or Ellipse Axis 2 Makes Line lie along the 2nd line or object Line or Ellipse Axis LLAN or Line or Ellipse Axis Forces a line to be parallel to the X-Axis. Line or Ellipse Axis or 1 or 2 Forces two points to Two Points have the same Y- Coordinate Line or Ellipse Axis or Point Point (no 2nd choice required for Line) LLAN means "Looks Like A line," A part edge or projected feature 2

5 Coordinate Forces a line to be parallel to the Y-Axis. Line or Ellipse Axis or 1 or 2 Forces two points to Two Points have the same X- Coordinate Forces two lines to the same length and arcs Line, Arc, or Circle 2 and circles to the same radius Line or Ellipse Axis or Point Line or LLAN Arc or Circle Point (no 2nd choice required for Line) Line or LLAN 2nd choice must be same type as Arc or Circle first Point (center, end, or mid) 1 Fixes the point in the coordinate system Point (none) Circles & Arcs can still change radius and lines can change length Line, Arc, or Circle 2 Fixes the object in the coordinate system Line, Arc, or Circle (none) For circles, fixes both the center and the radius. End points and/or lengths of arcs and lines can still change Line, Arc, or Circle 3 Line, Arc or Circle Normal, Forces objects to be then construction, or mirror images about an Line, Arc, or Circle corresponding centerline for the axis Line, Arc or Circle 3rd pick LLAN means "Looks Like A line," A part edge or projected feature 3D Constraints There are: 4 Assembly constraints used to position parts in relation to each other. These are:, Angle, Tangent, & Insert 2 Motion constraints used to control rotation and/or translation of pairs of parts such as gears 1 Transitional constraint used to relate the motion of a follower and a cam Assembly Constraints DOF symbol One of the parts is the Grounded part with no degrees of freedom. All other parts are constrained to the ground or each other. If you move the grounded part all other will follow when you update. 3

6 Assembly Constraints Angle Tangent Insert These are numerous combinations of the four assembly constraints and their object choices. In addition, every constraint has an optional Offset or Angle that can be be positive or negative. The object choices are: Points: vertices, centers of circular features, work points. Lines: Linear part edges, cylindrical axis, work axis. Faces: Planar faces, work planes, cylindrical faces. Driving Assembly Constraints & The Contact Set Marked components are in the Contact Set Angle constraint between two faces to control and drive motion Translational Rotational Name 1st Choice, On Solid 1 2nd Choice, On Solid 2 Offset Remarks Vertex, Center of Vertex, Center of Arc or Circle, Arc or Circle, Work Point Work Point 3 0 Moves 2nd part from 1st part along World X- axis. Vertex, Center of Arc or Circle, Work Point Work Axis 2 0 Moves 2nd part from 1st part along an axis perpendicular to the edge Vertex, Center of Arc or Circle, Face, Work Plane 1 0 Work Point Positive moves point from face along direction of arrow. Work Axis Work Axis 2 2 Separates the lines along axis perpendiualr to first line Positive or negative offset both move the same way Work Axis Face, Work Plane 1 1 Positive moves point from face along direction of arrow. Moves centerlines cylindrical shape cylindrical shape 2 2 apart. Direction is determined on order of selection not sign of Positive or negative offset both move the same way offset. 4

7 Name 1st Choice, On Solid 1 2nd Choice, On Solid 2 Translational Rotational Offset Remarks cylindrical shape Vertex, Center of Arc or Circle, Work Point 2 0 Constrains centerline on radius (of offset) from point. cylindrical shape Work Axis 2 2 Constrains centerline on radius (of offset) from line cylindrical shape Face, Work Plane 1 1 Positive moves point from face along direction of arrow. Face, Work Plane Face, Work Plane 1 2 Positives separates faces, Negative interferes faces. Flush Face, Work Plane Face, Work Plane 1 2 Moves 1st part in direction of arrows. Negative moves in direction of arrows Angle Face, Work Plane, Edge, Work Axis Face, Work Plane, Edge, Work Axis 0 2 Included angle between Picking an edge displays the positive arrows an arrow (vector) (vectors) Name 1st Choice, On Solid 1 2nd Choice, On Solid 2 Translational Rotational Offset Remarks Tangent Cylindrical Face Cylindrical Face 2 2 Moves perpendicual to the cylicrical face 2nd solution changes side of face that is tangent Tangent Cylindrical Face Face or Work Plane 1 1 Positive move along direction of face arrow One choice must be a cylindrical face. Tangent Edge, Work Axis, Center line 0 0 Cylindrical Face This constraint can be applied but has no effect whatever! Insert Cylindrical edge on part Cylindrical edge on part 3 2 Positive separates faces. Is a combination of mate two centerlines and mate two faces. You can pick the second solution and get a Flush. Motion Constraints Motion constraint controls rotation of pairs of parts such as gears. Pick faces of gears. Ratio is number of rotations for 2 nd pick relative to 1 st. For complex trains such as a planetary, Ratio must be a formula based on analysis. Second Type applies to a rack & pinion 5

8 Transitional Constraint The transitional constraint maintains contact between two surfaces one of which moves. There is no offset in this constraint Contact Solver If components are in a contact set and collision occurs when one component moves: 1. If the second component can move it will. 2. If the second component cannot move, motion of the first will cease 6