Graphics Systems SolidNotes

The right part. The wrong stress.

When analyzing a SolidWorks assembly within COSMOSWorks, the available results to plot are initially displayed for the entire assembly.  But I'd like to tell you about a trick to change that. And it might be the most important COSMOSWorks trick you learn this week.

Here in the image on the left, we see a simple, two-piece assembly and we're plotting the normal stresses in the Z. Note that the maximum stresses occur within the piece to the left. Let's call that the "collar."  The second piece- we'll call that the pin shuttle- comes in to contact due to the loading and we're interested in the stess concentrations and maximum stress there.  What do you do??

First, you must hide all components you are not interested in. Secondly, right-click the chart results in question and modify the Chart Options. You will be then presented with a checkbox option to show the Min/Max range on the shown part only.

After this, you may need to re-edit the definition of the plot but afterwards, the plot will correctly display the stresses, displacements, or strain for the desired part only.

You can see the modifications in the image to the right. And now you know how to tweak your plots from assembly analyses to correctly show results for specific component!

COSMOS FloWorks user? Wanna grab the EV of 08's SP4? Read here first.

So you say you've been waiting and waiting and waiting for SP4 of SolidWorks 2008.  And you've seen the download for the EV (early visibility) release on your Customer Portal.  But now you're wondering if you should download it.

If you're a COSMOS FloWorks (SolidWorks' Computational Fluid Dynamics software) user you might want to think twice. Why?  Because Flo studies are not backwards compatible to the previous Service Packs.

Straight from the horse's mouth.... or better, the SolidWorks Knowledge Base, see Solution Article S-016109. Users who've upgraded to SP4 will be greeted with a message "Wrong file format" but SolidWorks will still load. The answer to this article: "COSMOSFloWorks is not backward compatible. Upgrading the machine with COSMOSFloWorks SP2 to SP4 will correct the "Wrong File Format" error message. Unfortunately there is no work around other than recreating the model using the SP2 version or upgrading to SP4."

This means that if the company is going to upgrade its users, all the users ought to upgrade, even if only one or two are FloWorks users.  This should cause the CAD administrator and the user community to think twice before haphazardly downloading and installing new service packs. As always, if you have a question or concern, please call your reseller first and let them offer their input and help guide your decision. (This is also a good time to 1. make sure your organization has backups and restore points and 2. keep an eye on those individuals who are always the first to grab new releases and install them independantly from the rest of the community)

Add it in!

We're all familiar with SolidWorks Add-Ins such as COSMOSWorks, PhotoWorks, or Third Party items such as DriveWorks. But did you know that some productivity softwares, such as MS Excel also utilize add-ins? It's true. Furthermore, you might realize that you are already using one! If you don't know, allow me to show you- in MS Office 2007- where to go. So, start up Excel... go ahead...

At the bottom corner of the Start menu for Excel, you'll note the Options button.

Note the "Add-Ins" category. By selecting this you can see what add-ins are available and which are active or not. Some add-ins are loaded when you install some other piece of software. Others are additional content for and through Microsoft Excel that need to be downloaded before using. (You can select the images to make them larger)

Here to the left, I clicked "Go" from the previous screen and you can see I've chosen one of the add-ins provided to us by Microsoft. This particular add-in allows me to perform histograms, covariance analysis, and random number generation among others.

So what?  What could this possibly have to do with SolidWorks. Well, quite a bit if you frequently work with Design Tables or use third-party SolidWorks add-ins such as DriveWorks. Both of these examples heavily rely on Excel. For example, if we used a design table to capture important dimensions of a part and the MROUND command to round up the values for displaying within the part drawing, we would be concerned if whether the Excel Add-In that contains that function was installed lest the design tables fail to round the values accordingly.

This problem, like others with Excel, can often be abrogated by simply insuring that you are using the most recent version of the tool. This however isn't always available as an option. So, as a friendly reminder from another SolidWorks user who has been bitten in the backside by Excel, please be sure to check your add-ins. (especially if your company is upgrading from one version to another) And who knows? You might find that useful command you were looking for that you never thought Excel could do!

If you are a DriveWorks user then setting up Excel shouldn't be something new. Along with Add-Ins, you also have macro and security settings to consider. But this, as the expression goes, is "another episode."

SolidWorks File References

SolidWorks External Reference Search Order

(from our "Secrets of File Management" SolidWorkout)

When any parent document is opened, all documents that are referenced by the parent document are also loaded into memory. In the case of assemblies, components are loaded in memory according to the suppression state they were in when the assembly was saved.

SolidWorks searches for the referenced documents in the following order:

1. RAM (Random Access Memory)

If a file with the correct name is already in RAM (active memory), SolidWorks will use that file.

2. User Defined Paths (The directory paths specified in the Folders list on the on the File Locations tab in Tools, Options)

Users may establish a list of directories for SolidWorks to search before the software’s default searches are performed. Generally, these directories would be shared network locations where projects are stored. Establishing this list is optional and must be enabled by checking the Search File Locations for External References option on the External References page of Tools, Options, System Options. Setting this option can be useful in a collaborative environment where the current copies of the work files are stored in a common directory on the network.

3. The last path you specified to open a document

When you open a parent document, SolidWorks will search in the same directory for referenced files.

4. The last path the system used to open a document

This applies if the system opened a referenced document last.

5. Relative Path (The path where the referenced document was located when the parent document was last saved)

This is the path stored in the parent document except that the drive (C:\, D:\, etc.) is considered to be the current drive.

6. Absolute Path (The path where the referenced document was located when the parent document was last saved with the original drive designation)

This is the absolute path stored with the parent document.

If the referenced file is not found after these steps, SolidWorks turns the process over to the user to browse for it.

Note that all updated reference paths in the parent document are saved when you save the parent document.

File names should be unique to avoid bad references. If you have two different parts called bracket.sldprt, a parent document that is looking for the part will use the above search order and use the first part it finds with the name it is looking for.

SolidWorks Corporation purchases Priware

Effective today (3-26-08), SolidWorks Corporation has purchased Priware from the UK. Priware is the developer of CircuitWorks. While "CircuitWorks Lite" has been incorporated into core SolidWorks for some time (and will continue to be in the future), the full-blown CircuitWorks software will now be part of SolidWorks Office Premium.

There are two functional changes going forward:

1. Customers who have SolidWorks Office Premium will get CircuitWorks at no additional charge, starting with SolidWorks 2008 SP 4.0.

2. Customers who have CircuitWorks will have their corresponding SolidWorks seat upgraded to SolidWorks Office Premium at no charge.

Interesting and Insightful COSMOSWorks answers, Part III

I'd like to address some of the many COSMOSWorks questions we here at Graphics Systems see come through during training or everyday Technical Support.  And we thought that, instead of sharing the answers with lone individuals or just those who took training classes, we'd publish them "for the greater good."  To begin with, I'll deal with a couple of mesh-related questions.

1. Can the use of mesh control still cause distortion in an element? Great question! The use of Mesh Controls is meant to do just the opposite: fix distorted or failing elements. However, given the right conditions, one could still create an undesirable mesh with poor aspect ratio.  We'll deal with aspect ratios below.  In general, your use of mesh controls is a considerably safe bet.
2. What is a good guideline for aspect ratio check on my mesh? Aspect ratios, which we'll cover more in a future post, are a mathematical check for amount of element distortion (how an element gets mapped along curvilinear geometry) within a mesh. Ideally, every element of a mesh will have an aspect ratio of 1. But that's just not realistic given models that look more like reality than tinker toys. And so it is suggested that if there are approximately 5% of all elements diverging from a ratio of 1, you should be OK. But having very distorted elements isn't neccessarily a bad thing because they may be in areas of your model where accurate results aren't needed. To check this, after a mesh has been created we can create mesh plots of both aspect ratios and Jacobian checks. We'll cover more on this sub-topic as well in a future post.
3. With a p-adaptive mesh, what is a good threshold for the "energy norm error?" There are no hard and fast rules for this but, from the kind folks over at COSMOS, it is recommended to target within 10%.  Take care, however, that (like above) certain areas of your model may be of less interest than others, and refining the mesh in areas of importance is a good way to go.

Lastly, there are two other questions I'd like to deal with. the first involves the use of a "pin connector." Instead of modeling and including a real pin between components, if one isn't interested in the displacements and stresses within the pin itself, it can be excluded and replaced with a special connector. However, this connector creates special bonded pairs and so no gap can ever exist between the pin and the bore. In order to have and use a gap, a pin must be modeled and included within the study. This means it will have to be meshed and solved along with the rest of the components. You also must create a No Penetration contact condition between the pin and the components it connects.

Finally, for studies with beam elements (versus shell or solids), the user can retrieve the forces on the beams with COSMOSWork 2008 by simply right-mouse clicking the Results folder and selecting "List Beam Forces." Also, if you're new to 2008, check out the other new plots you can now create with studies that use beam elements.

Thanks for reading!

Getting WMF out of SolidWorks

Often times people want to get nice, vector-scalable artwork out of SolidWorks for use in technical publications. An easy way to do this is to make a blank drawing sheet with the view(s) you want, and then save it as an Adobe Illustrator file. For Tech Pubs departments that use higher-end publishing tools, that works just fine.

However, what if you're a smaller shop and you don't have Adobe or Quark products? What if you use good ol' Microsoft Word? In the past, you could just bring DXF files into Word, but that functionality actually went away in Word 2003 -- I was as suprised as anyone when I found that out! So, then what? Word can't take in an AI file. You could print the SolidWorks drawing to a Postscript printer file, and then manually doctor it up so that it looks like an EPS, but that's kinda dark arts type stuff (and the resulting file wouldn't have a TIFF preview). Are you condemmed to using raster images in your Word documents?

Not if you have a little $38 program called docPrint. It's from an innovative little company called VeryPDF. They have all kinds of useful tools for dealing with document and image format conversion. I was able to get vector-scalable line art from SolidWorks drawings, and also get very high-quality, scalable art from SHADED views, right from the 3D model, using this software to make Windows Metafiles (.wmf and the newer "enhanced" .emf). You can even try it for free to make sure it works for what you want to do. Check out www.verypdf.com and look for the docPrint product.

SolidWorks World Tuesday

This morning the general session featured more excellent speakers. Dr. Don Norman of Northwestern University won the Franklin Medal in 2006 (past award winners include Marie Curie, Albert Einstein and Stephan Hawking) and he's quite famous in design circles (just Google him and you'll get a ton of hits). He gave some great examples of why design needs to be for the user and not for the designer. Pick up one of his books to learn about his philosophy in depth as I can't really do it justice :).

Dr. Robert Ballard is most famous for finding the HMS Titanic, but he is one of the world's foremost oceanographers; if you've seen many Discovery and Science Channel shows related to undersea exploration, you will recognize him instantly (he was also the guy who did the "real science" segment at the end of every episode of the old Seaquest: DSV sci-fi TV show). What I took most from his talk was that by 8th grade, you've either got a new scientist/enginner or you've lost them. Both of my brothers are classically-trained teachers and I have heard the same thing from them many times -- middle school is where personality and behaviors are set in. I resolved during this talk to take a more active role in somehow reaching out to kids in that age group, both as a professional in the engineering world and also as an amateur scientist (astronomer, in this case) to spark real interest in the science and engineering. I have a few ideas but I'd love to hear about any you may have!

One tool that SolidWorks Corporation has developed that I think will be useful is SolidWorks for iPod. No, it's not a software solution; it's a website that has cool videos, renderings, and technical tidbits that are made for the iPod. SolidWorks thinks this is such a great idea that they gave every regular attendee of SolidWorks World an iPod Nano loaded with this content! See www.solidworks.com/ipod to get content for your own iPod.

SolidWorks World Monday

After yesterday's debacle in Green Bay, I was happy to turn my attention full-time to all things SolidWorks. This morning's guest speakers were very good. Danny Forster of TV's "Build It Bigger" gave a humorous and interesting talk tying together style and engineering from an architectural perspective. Theo Jansen of Holland is an artist who makes what he calls "beach creatures" that are mechanical automatons that are powered by nothing more than the wind. Google him and you'll find some fascinating articles and video on his work -- really thought-provoking!

Being from the original Dairy State, I did find it humorous when, at this morning's breakfast, they ran out of milk for the stacks and stacks of cereal displayed on the tables. I guess California cows may be happy, but not very productive compared to Wisconsin cows!

3DVia is a hot ticket on the showroom floor. This is an awesome solution for creating truly interactive documentation for tech pubs, as well as mockups of super-large assemblies. We'll be showing it at Graphics Systems in the near future! Take a look at the information on www.solidworks.com.

Interesting and Insightful COSMOSWorks answers, Part II

In Part I of our multi-partseries on COSMOSWorks Q-n-A, we covered three questions pertaining to Frequency Studies.  This time around, I'd like to handle a few more questions involving Buckling studies and "soft springs."

1. What can COSMOSM or GeoStar handle for Buckling that COSMOSWorks can't? The good news is that all products can handle both linear and non-linear buckling scenarios. The user must choose the correct material model for each case.
2. Can Slenderness Ratios and Euler Numbers be retrieved from the results of a Buckling study? COSMOSWorks does not report back these values but they can be calculated by hand.
3. When "soft springs" are used to stabilize a model, can the reaction forces on these "springs" be retrieved?  No; the soft springs are additional qualities to the stiffness calcs being performed. But with all static studies ran with COSMOSWorks, the user can retrieve and list the reaction forces and moments for selected items or the entire model. This is a great, quick check to ensure that your model is balanced and truly.... static. (Right-mouse click the Results folder and select List Reaction Forces)

In our next installment, we'll wrap things up with questions involving meshing, pin connectors, and beam elements.