Solid modelling freed of legacy constraints
Inventor 2 from Autodesk
The second release of Inventor, Autodesk’s non AutoCAD features based modeller is now available.
Freed of legacy AutoCAD constraints, Inventor offers an optimised 3D modelling environment as exemplified by Solid Edge and SolidWorks.
Despite the undoubted benefits of the ground up development, as a first release it could not deliver a comprehensive range of modelling capabilities and more surprisingly only limited drafting and AutoCAD compatibility.
For traditional AutoCAD sites the natural progression to 3D in the form of Mechanical Desktop has been complicated by the appearance of Inventor as Autodesk risks sending a confused message to users by maintaining both products.
Their stated policy of ‘continuing to improve Mechanical Desktop for several releases beyond Release 4’ for users needing surface modelling and complete AutoCAD integration inevitably raises the question as to what will then happen.
Autodesk’s rationale for shifting to Inventor for large assemblies, ease of use plus future surface and add-on modules avoids the issue of whether the other already more mature mid range packages will be equally as familiar and compatible to AutoCAD users.
While this debate rages, Release 2 incorporates new modelling functionality including sheet metal design, performance improvements and drafting enhancements.
The interface has a contemporary Windows modeller style of toolbars and feature browser.
The panel bar is a floating or dockable palette that displays a context sensitive selection of tools appropriate to the current mode such as sketching or creating a feature.
This can be displayed in ‘Learner’ mode with text alongside each tool or the more compact expert mode with icons and pop out sub menus only.
The extensive help and training facilities that include animated “How To” topics in the DesignProf and Design Doctor are supplemented by the Sketch Doctor to manage sketch relationships and to diagnose them for use in specific features.
Reference dimensions driven by part geometry can be added to sketches and profiles to be revolved can be dimensioned by diameter rather than just the radius that exists in the sketch.
AutoCAD geometry can be imported directly from model or paperspace to create feature profiles.
A show all constraints displays a symbol frame for each sketch element containing both manual and automatically generated constraints.
Dimensions for any feature can be displayed over the model for editing if required.
Model manipulation is improved with drag and drop facilities for reordering features or parts in the design tree, creating sub assemblies if required.
Features can also be dragged within or between part files to create copies or saved out as design elements for later use.
Complete parts can be saved as mirror or derived parts that maintain associativity to the original editable parent.
In addition to the standard modelling capabilities, parts can now include taper and spirals and control of fillets is greatly enhanced.
A single fillet feature can include multiple edges of constant or variable radius with options for blend and transition control.
A sheet metal environment is now available using a consistent sketching interface but with dedicated tools for flanges, corner seams and bends.
Material thickness, default bend radius, and other sheet metal-specific settings can be specified and a feature library offers standard dimple, keyhole and D connector features.
Although the part can be modelled in its true 3D form, a flat pattern is continuously updated as features are created.
Fortunately a number of improvements have been made to the detailing environment.
A wide range of drawing standards are supported and complex multi-segment sections can be created to illustrate complex geometry.
Model parameters can be placed anywhere on a drawing sheet rather than being tied to dimension placement in specific views.
Parts list and balloon callouts are also improved.
Assembly modelling is enhanced with the ability to use faces on other components to terminate features to achieve true in context relationships.
Components can also be patterned to speed up the modelling of equally spaced standard components.
Existing Mechanical Desktop parts can be linked into Inventor assemblies.
A graphical dialog and model preview aid the creation of inter-component constraints.
Partially constrained components can be dragged within their remaining degrees of freedom for interactive motion.
The drive constraint tool allows a single constraint to be stepped through a sequence of values to simulate motion.
Animated exploded views can be generated using integrated key framing tools.
Each explode step or ‘tweak’ is accessible for editing from the browser with movement trails that can be toggled on or off.
Once an exploded view has been constructed it can be saved out as an AVI animation or used as a drawing view.
Multiple presentation views can be created for each assembly but rather than being saved in the assembly file itself they are saved to a stand alone presentation file, thus increasing the number of associative files further.
The Design Assistant is available to help manage design files within Inventor or externally including options for ‘where used’ searches.
The Link Manager is used to minimise the risk of broken parts or lost dependencies when it is necessary to move, rename, or copy files.
There is however an unnecessary AutoCAD feel to the need to set paths for referenced files to be found within a model.
Microsoft’s NetMeeting is supported in order to be able to create a remote on line meeting to collaboratively manipulate a model even if the other parties to the meeting do not have an Inventor license.
The second release of Inventor is more capable but still does not offer the complex 3D sketching or surface capabilities of the leading design centric modellers.
Being a less mature product the less obvious functionality such as the ability to write an STL file for rapid prototyping from an assembly is missing.
If Autodesk truly do need a non AutoCAD modelling platform, Inventor has probably been launched just in time to prevent defection while ground is made up.
In the meantime, Inventor does offer some Mechanical Desktop integration benefits but the trade off against the more extensive modelling capabilities elsewhere will largely be a matter of personal preference.