Ellipsis

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  Ellipsis is the official blog of Autodesk's Technical Evangelist Team. We will discuss all things design and manufacturing related with a focus on industries such as automotive and transportation, consumer products, industrial machinery and building product manufacturing and fabrication. We also have resident experts who will blog about specific product developments in CAD, Simulation, Industrial Design and Data Management.

  We look forward to providing you, our user community, with the most relevant and up to date developments in our industry, and hopefully with information that will assist you in doing your job better, faster, and more precisely.

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  The same, but different...
  October 1, 2009 09:30 AMby Jay Tedeschi

  The same, but different... let me explain.  So, the same problem we were discussing for the last couple of weeks, namely, working with data from other sources.  If you recall, I had covered working with data from a vendor from whom I was buying components for our re-design.  This week, the problem is the same, but different in that in this case I am working not with a purchased component, but rather with an assembly that was created with a different design tool than the one I happen to use.

  In the best of conditions, this presents something of a challenge, but when we find ourselves needing to change the design in some way, the level of complexity quickly increases.  Autodesk Inventor Fusion was built from the ground up to facilitate the toughest of these type of design challenges.  In this, the first of several posts featuring Inventor Fusion, we will take a look at some basic assembly manipulation and modeling techniques.

  If you remember last week we finished up working on the Caster Wheel "Assembly" that we downloaded from our vendors web site.  Well now we are going to work on the brake assembly that attaches to two of those wheels... this was originally created in Pro/E, which is not a problem for us as we can open the .asm file natively.  Once open we can see that the existing torsion spring is not going to work in our new configuration, so we will select the body from the assembly, and then from the marking menu select "Isolate" to suppress all but the spring.

  

  I can now make several non feature based edits to this part, quickly and easily.  As these changes are symmetric, I will split the part, then correct for rotation and position with the Move command.  Here I am moving the body along its mount axis so that it fits correctly in the bearing block.

  

  Now we can address some of the feature lengths, but again, not via a feature edit, but rather with a direct manipulation of the feature face.  For example, as you can see in the figure above, the length of this element is a bit more than is required, so Press/Pull functionality is used to select the capping face and then press into the model, shortening the element.  As we split and then moved the entire body away from the center plane of symmetry, the split face is now short of the center plane by the amount of that first move.  Press/Pull is used here again, but in this instance I will select the symmetry plane after picking the capping face, and the pulled face "snaps" to that plane.

  

  Finally, the corrected spring is mirrored about the symmetry plane and the assembly saved for use back in the top level assembly.

  

  The thing that really hits you with Fusion is how absolutely easy it is to use.  The entire edit sequence shown above took no more than a couple of minutes... Don't take my word for it... check out the entire session for yourself in this video I shot.  As always, if you have any questions or suggestions I would love to hear them.

  Ciao'

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  Weight Watchers...
  September 16, 2009 12:27 PMby Jay Tedeschi

  For those of you who remember my post from last week you may recall that we had a small problem with vendor supplied library component data, namely it's construction did not allow for any type of mechanical functionality within the top level assembly. Fortunately, we were able to use Inventor's multi-body tools to break the caster chassis into several parts that we then reconstituted as a proper assembly, allowing for rotation around it's own spindle axis.

  Well, that is just one of the problems that is encountered when working with data such as this. A larger problem from a physical standpoint, is that the property data for any part that is not modeled with 100% geometric accuracy is not going to be valid.  If I take a look at a cross section view of the caster wheel assembly in question, it becomes quickly evident why this problem exists.  Take a look at the image below...

  

  As you can see, this caster has no internal structure whatsoever... it is quite simply a solid part whose exterior closely matches that of the actual component.  From a mass properties standpoint, this is really bad.  Fortunately, there is a way to correct for this, and it is incredibly easy.  With the Caster Assembly open, I navigate to the browser and highlight the top level assembly... then right click and select iProperties.

  

  Next I select the Physical tab and activate it.  In the middle of this dialog box are the the General Properties for this assembly.  Notice the calculated value for Mass...

   

  A quick look at the product data sheet from the vendors web site shows the weight of this part to be .4536 Kg... less than half of what this is currently. By selecting the Mass field, I can highlight the current value and then overwrite with the value determined from the product sheet.

  

  Notice that when I do this, the calculator symbol changes to a hand, indicating that the calculated value has been over-ridden.  Any assembly that this caster wheel is placed into will now calculate the correct overall mass properties, as well as displaying a combination of the hand and calculator, to show that the data contains some Mass over-rides.

  I have posted a video to my YouTube channel that shows this entire workflow, as well as a little bit more with regard to setting default BOM structure and adding BOM properties.  I hope you find this useful, and as usual, if you have any questions at all, please let us konw and we will do our best to answer them or find someone who can.

   

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  Simplify...
  June 19, 2009 02:38 PMby Jay Tedeschi

  Simplify... as defined by Websters...

  Function: Transitive Verb

  Inflected Form(s): sim.pli.fied; sim.pli.fy.ing

  Etymology: French simplifier, from Medieval Latin simplificare, from simplus simple, Date: 1759

  : to make simple or simpler: as a: to reduce to basic essentials b: to diminish in scope or complexity : streamline <was urged to simplify management procedures> c: to make more intelligible : clarify

  "Mmmmmm... that sounds good. I'll have that."  Wow, enough references in the first few lines to make Dennis Miller proud. [grin]  However, in all seriousness, when working with simulation, your goal should always be simplification.  Simplify.

  

  Ultimately, your goal is to analyze as accurate a representation of your assembly as possible.  But before you dive in with your top level file, think for a second as to what results you are trying to determine.  The assembly shown above is an excellent example... my goal was to determine the deflection of the welded chassis under load, therefore the rear trolley wheels and forward pivot mount are not required.  Their role in the analysis can be simulated with a constraint.  Ditto for all of the pylon mount points and the associated hardware located on the upper faces of the weldment.  These changes alone will save me an incredible amount of time in pre and post processing.

  There is however, more that I can do.  Take a look at the weldment assembly itself.  What one feature or characteristic do you notice almost immediately.  Right.  It has symmetry... and as long as the loads placed upon the trolley via the engine pylon are also symmetric, which they are, what assumption can I make with regard to the results?  Correct... they should also be symmetric about the center plane of the weldments.  So what can I do to simply this and still get accurate results?  Take a look at the following image...

   

  I am using a Level of Detail Representation, named "Simulation", for each of the Weldment sub-assemblies.  An LOD Rep in the top level assembly with the same name allows me to toggle back and forth.  Now in this situation, you have a lot of flexibility in how you create your simplified rep, but the easiest is to use a Shrinkwrap substitute and then drive a single extrude cut from the mid-plane out effectively removing half of each of the sub-assemblies.  The results are shown below...

  

  Sweet... right?  Okay, I am almost there... What?  You didn't think I was done did you?  Absolutely not.  What would happen if I was to load up this model the way it is now?  What do you think would happen to those unsupported elements that have all now been split?  Right... they do not effectively represent our full assembly any longer, precisely because I split them in half, and therefore I will not see the correct amount of deflection on those elements.  I can't use a Fixed constraint either, as it will leave me with a frame that is unnaturally stiff.

  The answer is the Frictionless constraint. 

  

  This constraint prevents a selected surface from moving or deforming in the normal direction relative to the surface selected.  It does however allow for rotation, movement and deformation in a tangential direction to the selected surface.

  

  So... applying the Frictionless constraint to all of the cut faces on the Weldment Sub-assemblies allows me to simulate symmetry, and I now have an much smaller model to have to pre and post process... these are all very desirable attributes when performing analysis.  Meshing is quicker, automatic contact detection is quicker, and best of all, the results are in-line with what I would expect to see if I had spent almost three times as long analyzing the full assembly.

  

  Simplification... "It's a good thing." 

  By the way, if you found this interesting, and are looking for a way to get better acquainted with Inventor Simulation, then you should head over to @adskcommunity on Twitter and send them a direct message to receive your copy of "Up and Running with Autodesk Inventor Simulation 2010".  Details are on the site.

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  All Mixed Up...
  June 11, 2009 03:01 PMby Jay Tedeschi

  If you frequently find yourself working in a "mixed geometry" environment then do we have a new tool for you... Up on //Labs today, the release of the Rhino Import Translator. http://tinyurl.com/nb8ul5

  

  This translator allows Inventor users to directly read Rhino surfaces, solids, wires and points, eliminating the need to intermediate file formats such as Iges or Step.  Check it out... !

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  Interoperability or Collaboration...
  April 10, 2009 01:08 PMby Jay Tedeschi

  Heres another post from Rob Cohee, our resident BPM expert... Enjoy!

   

  I’d like to expand upon a discussion thread that I saw on Facebook the other day. It had to do with which application should be applied toward a particular design challenge. Or to be specific, should I use Inventor, or Revit, or Maya, or MAX, or Navisworks, or Alias, or AutoCAD, etc. Yes – use them all, the key is how to determine which one to use. It’s simple really, ask yourself “what is my desired result.” The answer to that question will determine which application, or combination of applications to utilize on a project.

  Here’s an example – I want to build a new line of configurable office workspaces. Simple enough, sounds like I fire up Inventor and start creating iAssemblies, right? Well, what if you were working with an Architect to build out a project? Maybe starting with the Revit file to perform some early analysis of the project would be appropriate? Here is where we can start to talk about the difference between interoperability and collaboration. At this stage I want to collaborate with the Architect. I don’t want to, nor do I have any influence to change the design of the building, so I’m not looking for interoperability between Revit and Inventor. However, by utilizing the Revit model to bring in the information I need to perform my analysis on these workspaces I have saved myself a considerable amount of time compared to re-drawing or re-modeling the architectural space. I don’t in this case, require interoperability between the Revit files and Inventor – I just need some sort of collaboration between the two.
  Let me expand then on what I mean by interoperability. Interoperability, in this example, would be the ability to open a Revit project file natively in Inventor – AND be able to manipulate the native geometry through parametric or other methods. So if I wanted to move a wall, I could click on the wall and have Inventor recognize the Revit wall element and move, clean corners, adjust schedules, door position, window position – essentially all the things that Revit does, but do it within Inventor. That’s interoperability, and that’s not what you want.

  THUD! That’s the sound of someone hitting me on the back of the head with a bat. “What are you doing telling the customers that what they want isn’t exactly what they want?” Sorry guys, that’s the cold hard truth of it. Where is the control in the design process if everyone can edit anything whenever they want? Plus, when you create a single, monolithic application that is good at many things; they become average as a complete solution. Here’s my thought - apply the appropriate technology determined solely by the desired result allows you to determine which purpose built tool to apply to the design; with a higher degree of accuracy and unmatched ease of use. Any one of the Autodesk products previously mentioned is best in class at modeling, drafting, collaborating, and managing every aspect of a project throughout its lifecycle. Check out this example...

   

  This should get some blood pressure up... Bring on the comments!

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  DP and BIM: BFF
  March 26, 2009 07:33 PMby Jay Tedeschi

  Well, it's spring and there are a few changes around here that I have to let you know about.  First of all, I am no longer the sole evangelist for the Manufacturing Industry Group, I am now part of a team of evangelists that resembles the lineups of the great New York Yankee teams of the 60's, 70's and late 90's.  Powerhouse is the word that comes to mind, and we will deal with the introductions at a later date, but suffice it to say that it is a VERY strong team and I am proud to be part of it. Oh... the things we are going to show you...

  So, this is no longer my blog, but rather it is now "our blog", and without further ado, I will turn this post over to Rob Cohee, Industry Solution Evangelist specializing in Building Product Manufacturing... or BPM... the first of many new acronyms you are all about be innundated with... [grin]

  DP and BIM: BFF’s?

  Wouldn’t you know it, as soon as the industry begins to collaborate in ways that is challenging contractual agreements on building projects now all of the sudden everyone wants BIM content, aka Revit Families. And the exchange process has to be quick and easy and… Oh yeah, don’t give away the farm when you pass the design to an architectural firm, plus the architect isn’t necessarily looking for something they can create CNC code from anyway. And what about integrating the product into the buildings infrastructure, plugging in MEP elements so that the manufacturers model can participate in the BIM project?
  Sounds to me like architects are asking me to make a new lightweight version of the model that I have already exceeded my engineering budget for. I don’t even know if they can accept .SAT, .IGES, or the new one, the all popular .DMWISYUWBATRA (Doesn’t Matter What I Send You U Won’t Be Able to Read it Anyway) file type. Some people prefer the longer version of the new format which is the .DMWISYUWBATRA-YERA (You’ll End up Re-modeling it anyhow).
  That’s right, I just came up with the longest acronym in Autodesk history. I’m so proud…there are so many people to thank… tears are welling up… eh eh ehmm.
  Ok, sorry about that – very proud moment. SO, you don’t want to give away the farm when people ask for your designs and you don’t want to spend any time making a dummy version of your gazillion part assembly. Groovy, neither did I and now we have something that will make your day (insert dramatic pause and drum roll here..). We now have Shrinkwrap! Stay away from the Seinfeld references here guys… Seriously this is killer functionality that is not only going to allow you to collaborate with people that are asking to include your designs in with their projects; it’s an opportunity for BPE manufacturers (see another acronym – Building Product and Equipment) to drive new business opportunities. How impactful is it for architects to literally cut out one of your designs from a shop drawing and glue it down on to a drawing? (please, please tell me if anyone has heard of or has had to do this…)
  Here is how it works in the new AEC Exchange Environment click the option for Shrinkwrap. It’s a lot like Derived in an assembly – and should be used together when you need to get real specific on what gets packaged up, I’ll save that one for another post.

  Take a look at the detail here. Bolts, washers, nuts, welds – everything you could put into a model is typically in your Digital Prototype.

  

  You’ll want to play around a bit with the settings to give you the desired result for your company, but for the most part the interface is wicked easy to understand (just move to New Hampshire – had to work in a wicked reference). About 10% will do for me here, patch up the remaining holes and I now have a much more simplified version of this model.

  The preview shows me the areas where the parts were removed and the holes that will be filled in for me.

  

  Once I’m done with the shrinkwrap, hit Export Building Components, add the Component Type so that the design matches up with the appropriate SIC codes, include any relevant metadata and hit OK.

  

  It’s going to save out a .ADSK file. That .ADSK will be able to be read in Revit Architecture, Revit Structure, Revit MEP, AutoCAD MEP, and AutoCAD Architecture. The file is as native to those applications as a .RFA (Revit Family file) or a block in the AutoCAD applications.

  

  I’ll blog more on what is included in the file, how it can be integrated into a Revit project, and more in later posts. I’m getting a lot of questions about this new functionality which tells me that the paradigm is shifting so far beyond 2D shop drawings, and block libraries to a true collaboration within the design process. So no worries, I’ll get plenty of mileage out of blogging about AEC Exchange. Who said coming up with topics was hard…? (ask me in two years, right Jay?)
  Since I can’t think of a cool pen name…
  -Rob

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  What's the deal...
  December 11, 2008 09:39 AMby Jay Tedeschi

  What's the deal with digital prototyping?  Well, that is the question I was asked by Carl Alviani of Core 77 while at AU last week.  My response and a short demonstration of the workflow can be seen on thier site, buried in with the rest of the Autodesk University stuff.

  

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  Visibility...
  October 29, 2008 02:24 PMby Jay Tedeschi

  While working on this headset assembly last week it occurred to me that a good tip for working with derived parts was staring me in the face. I have a lofted surface that is used to shape the electronics package housing in this assembly. Not wanting to go through the motions of creating a surface like this again for the outer headset housing, it is far easier to use derive to do an associative copy of the face and then offset it for the material thickness of that part.

  

  So, the first thing I need to do is to mark the lofted surface as an exported object. Easy enough… I find the lofted surface in the browser and then from the right click menu I select “Export Object”. I save and am done with this file.

  Now, I start a new part, exit Sketch 1 and then select Derive from the palette.

  

  What’s going on? There are no surfaces to select, even though I clearly marked the lofted surface for export. Well, I actually missed a pretty important step back in the original part. I need to make the surface visible, as well as marking it as an exported object.

  

  So… back to the original part, I find the lofted surface in the browser and from the right click menu I select “Visibility”. Save and close the part, start a new one again, only this time when I run the derive command I see that the Lofted Surface is now selectable from the derive menu.

  

  What would seem to be a minor detail can actually cause you much angst if you are not mindful… so please… be careful out there!

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  Rule Fillet
  October 20, 2008 12:06 PMby Jay Tedeschi

  Well, as promised I will take a look at yet another unique area of functionality available to users of the Plastic Features Technology Preview. Today I will introduce you to the Rule Fillet.

  

  Rule Fillet… intriguing name isn’t it? For those of you who have backgrounds in surface modeling, this name may bring to mind something like this… S(t, u) = p(t) + ur(t), an algebraic description of a type of developable surface. However, in this case, Rule Fillet is exactly what it sounds like. Quite simply, it is a fillet which has as a characteristic a set of rules governing its behavior.

  Take a look at the image below… I have applied a Rule Fillet to a Rib feature. In the dialog box you can see that I have selected the entire feature as the source and have selected all of the edges of this feature as targets for the fillet.

  

  I do not however want the top or end faces of the rib feature to have filleted or rounded edges, so I must exclude them from the selection set. If I expand the dialog box to show additional settings, I have access to tools which will allow me to remove both individual faces and edges from the selection set.

  

  The advantage of setting up a fillet rule such as this is that if there are any geometric changes to the feature, e.g., rib elements being added or removed from the feature definition, the fillet will automatically be added or removed as well, without any additional interaction on the part of the designer whatsoever.

  

  A quick edit to the Rib feature, selecting an additional sketched line which was omitted previously updates the Rib network. Fortunately, because of the Rule Fillet, I do not have to restructure the part history, or edit the fillet to include additional edges as the new addition is included in the existing Rib feature and therefore is filleted automatically.

  

  A catchphrase in the software industry for years has been the ability to “capture design intelligence”. It could be argued that features such as Rule Fillet finally achieve this.

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  Getting Thin...
  October 12, 2008 01:44 PMby Jay Tedeschi

  Well, I’m back after a two week swing through Canada where I helped to deliver the Digital Prototyping message to audiences of Inventor users as well as users of our competing products. After presenting 6 times, in 6 different cites there was one dominant theme… the next generation of tools that Inventor users will have at their disposal are available right now on \\Labs. The new Autodesk Inventor Plastic Features Technology Preview is fundamentally different with respect to basic modeling tasks, different enough that it deserves some serious column time in the coming weeks.

  Today I am going to look at what will most likely be the first departure from the typical modeling methodology that you will encounter when using PFTP… hey, I know, not the best acronym ever, but it is significantly easier to enter on the keyboard. Anyway, consider the simple extrude command…

  

  Not quite as simple as it once was when I have additional things to consider with regard to wall thickness. For those of you who do a lot of plastic parts however, THIS is the ideal workflow as the part essentially understands that it is a thin walled part.

  In creating this electronics housing I will first need to cap the open top and bottom you see in the image above. In selecting the new “Thin” tab I have access to controls for plastic feature specific characteristics. With this part, I want to close the top and bottom and open the ends.

  

  If you look at the image above you can see that I first deselect the “Open Faces” From and To terminations. Next up I have to now select the faces, or more specifically an edge of the faces that I want to open.

  

  In selecting the “From Profile” option I can now open up the faces that you see in the image above. Ahhh, sweet success… the “finished” start of my electronics housing package.

  

  Next in this series I will look a bit more in depth at additional functionality of the PFTP. Hope you tune in to check it out.

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