CAD in Context, How Physical Parts Factor-In to Your Digital PLM World

Do you have physical parts laying around with no CAD? Have you invested substantial amounts of money in PLM or PDM systems, only to have a large portion of your products sitting squarely outside this system? As 3D Imaging has progressed, we see it converging with the regular digital domain of design. Via Imaging, you can take that “legacy” part, and get a 3D representation of it. How you use that data has been the question for over 10 years.

First, let’s talk about why your CAD or PLM system doesn’t understand 3D scan data. Now we see an apples-to-oranges problem: how do you take apples and make them into oranges? This presentation looks at the different generations of software trying to solve this dilemma. Closing with the latest generation, we see a way to take 3D Scan data, and make it work with our system, instead of outside of it. We look at a case study of a game controller, and how we can create everything from drawings to assemblies to tooling, just like a “real” part. The only difference being it wasn’t created in our PLM originally.

Monday May 17th, 8:30am-12:00PM

See how Reverse Engineering can be used, and get up to speed on the latest technology in the industry!

Using CAD Tools to Edit Your Mesh

There may be times when all you need is a nice water-tight mesh. Scan the part, run the Healing Wizard, maybe a Rewrap command, and presto! But what if you want to add a precise feature? Perhaps a few quarter inch holes for fastening locations or maybe you want to trim the part so that its an exact height. Well its a good thing you have Rapidform! In this post, I’ll show you how to use some of our CAD Tools on mesh bodies.

Overview

The main trick is that you need to remember that Rapidform is a history-based modeler. This means that if you want to use any surfaces or ref. geometry to edit your mesh, those features need to be above the mesh in the feature tree. I personally like making a copy of the mesh. This allows you to have an original copy in the file that you can always reference back to. So we just need to make the CAD entities we want to use to edit our mesh. Then we copy our mesh and use those entities on our copied mesh using the mesh tools.

The Scenario

In this post, we’ll use our Quick Start Guide sample model, the bottle. (C:\Program Files\INUS Technology\Rapidform\Sample\QuickStartGuide\Bottle.stl).

Our customer wants to take this scan of his and make a print out of the stl, but of course he wants some quick edits done. The printed bottle will eventually be made into a trophy on a stand, so they’ve requested that the height of the bottle be shortened by 0.315 inches. They’ve also requested that a clearance hole be modeled in so that they can tap and thread the bottle. It’ll be a 1/4-inch threaded post, so the hole needs to have a 7/32-inch diameter and be at least an inch deep.

Getting It Done

First we’ll create a plane that’s 0.315 inches above the bottom of the bottle. We’ll use this plane not only to shorten the height, but it will also serve as the sketch plane for our hole.

Conveniently the bottle scan is already aligned and its sitting on the Top plane. We can quickly generate a plane by using the CTRL key.

Thinking ahead, now we’ll use this plane for our 2D mesh sketch to make our clearance hole. The cross-section can referenced to make sure the hole is concentric (it happens to be centered around the origin), and the smart dimension tool will guarantee the size of the hole.

Using the sketch, we can extrude a surface (or a solid) that we’ll use to create the hole in the mesh. We need at least a 1-inch deep hole so we’ll extrude to about 1.15 inches.

Now that we have our tools ready, we’ll make a copy of the mesh using the copy and paste commands (Edit Menu).

In Mesh Mode (double-click on the Copied Mesh), we’ll be using the split command (Tools>Mesh Tools> Split). First we’ll split the mesh using Plane 1. Be sure to have “Cap Section Ends” checked, or if you prefer, you can use the fill hole command.

Then we’ll split the mesh again and use the surface body as the entity.

With a quick fill hole on the bottom, we have our mesh!

The result is a mesh file that has been modified with CAD precision, a unique feature found in your Rapidform Software.

Notes

A slightly different workflow can be used to generate the hole (or more complex shapes that one may encounter). Instead, you would convert the solid body into a mesh by making an empty mesh feature and using the “Convert Body” command. Then use the Mesh Boolean command (Tools>Scan Tools>Boolean) to cut (or merge or intersect) the shape.

Using the CTRL Key

While helping a customer with a support call the other day, I came across more proof that the developers are more clever than credited. As part of their strive to make sure the software is intuitive, a lot of the keyboard shortcuts used in one scenario, carry over to another. A great example is the use of the CTRL key.

The Tip

Did you know that the CTRL key can help you duplicate an entity in a speedy fashion?
Select an entity, then hold down the CTRL key, and click and drag. A copy of your item will appear and you can control its location by moving your mouse.

Now the most familiar time to use this might be while generating a ref. plane like shown in the previous picture. Or maybe you’re more familiar with the trick while duplicating sketch entities.

Did you know it works during the Loft Wizard too?

Or how about to generate additional points on a 3D curve?

This trick can be applied in a few other places as well. Its yet another way the software decreases work time, making you more efficient.

Since 1981 Rosenberg Ventilatoren GmbH (http://www.rosenberg-gmbh.com), located in Künzelsau-Gaisbach, has developed into an outstanding centre of the air movement and air handling industry by design and production of controllable external rotor motors. Rosenberg is a competitive medium sized company with around 1,400 employees worldwide and during the last 20 years, the Rosenberg Group has been complemented in Europe by several additional works in France, Italy, Hungary, Czech Republic and Germany.

With an annual production of about 120,000 fans, Rosenberg Ventilatoren GmbH currently exports 55% of the total company turnover and to keep the high quality of products, they aim to chase a continuous flow of information and good cooperation with their valued customers all the time. Furthermore, it is important to jointly achieve a continuous evolution of the quality of products.

The case study goes on to describe how they scan existing fan blades to generate CAD models.  And of course with XOR, the CAD models are editable because they have a full feature tree, with parent-child relationships (not just a bunch of imported surfaces):

As new project, they were looking for a solution provider who is able to measure a ventilator blade for qualified CAD modeling. The new project aims to create a precise CAD modeling for Highly-Effective Performance with lower noise and vibrations. It is always challenge for them to improve their products in terms of efficiency and noise and now they are quite keen to see new improvement with Rapidform XOR, the most comprehensive Scan-To-CAD application.

sigma3D (www.sigma3d.de), plays a role to serve the qualified CAD modeling using Rapidform XOR to Rosenberg Ventilatoren GmbH and Mr. Hubert Schwarz, Project Manager at Rosenberg is quite satisfied with the performance of Rapidform XOR. sigma3D uses a FARO laser scanarm for measuring, then imports it into Rapidform XOR to create a optimized polygon model in easy & quick way through “Mesh Buildup Wizard™”. This technology automatically processes the 3D scan data from multi-shot point clouds into a single qualified mesh. After that, to capture each geometry information interactively, Rapidform XOR is able to produce “Auto Segmentation” from the mesh model automatically based on feature region.

Of course, the real magic results come from what you do after you’ve gotten to a merged mesh.  The XOR technique of making CAD models for scan data is all about extracting design intent, then using real CAD tools (like extrude, revolve, loft, sweep, fillet, boolean and such) to build up a real CAD model that represents the scanned object.  This results in an “intelligent model”, meaning it’s feature-based and editable just like anything that can be designed in SolidWorks, Pro/E, NX, etc.  In the case of Rosenberg Ventilatoren’s fan blades, this means that they can improve upon an existing design and bring a new product to market in record time.

We all know that the Rewrap command is useful for interpolating mesh data as well as smoothing noisy data. This post continues our look at the command with a third example. The first two examples can be found by visiting this post and this post.

Example #3

Generating a mesh for cross-sections: Generating cross-sections can be useful if you plan on creating lofts. Using 3d-sketch tools, you can smooth out and edit your cross-sections to create smoother loft surfaces.  Cross-sections can also be used to generate sweep paths, guide curves, and boundary-fit curves. What if your mesh is missing data? Or there are mesh features that you would like to omit from your final model? If each cross section was a 2d section we could use our sketch tools to fit geometry over the missing data. Or if they are 3d sketches, we manually could fill in the gaps with matched splines, and delete sections we don’t want. Of course, a much more elegant method would be to use the rewrap command.

In this example we have a Rapidform helmet. Most us application engineers in the company put these on to protect ourselves from the sales reps when the end of the fiscal year nears…

The scan itself is missing data and there a few features that we want to ignore during our modeling. With region groups, we can easily separate the areas of interests.

After deleting the unwanted data, or copying and pasting the regions of interest, we can run the rewrap command to simultaneously fill holes and defeature.

Now we can generate continuous cross-sections for Lofts…

for Boundary-Fit Surfaces…



or to help with Solid Modeling.

Final Thoughts
This concludes this 3-part series of Commands and Applications for the Rewrap command. Want to request the same for other commands? Have other questions or comments? Let us know in comments below!

We all know that the Rewrap command is useful for interpolating mesh data as well as smoothing noisy data. This post continues our look at the command with a second example. The first example can be found by visiting this post.


Example #2

Autosurfacing a mesh for CAD operations: If you are creating an auto-surface of a model, it is usually said that a majority of the editing must be done to the mesh since you are creating a verbatim model. But with XOR, you have the added ability to create a hybrid model, that is, performing CAD operations on a verbatim model to create a model that has both the accuracy from the scan as well as the design intent of a designed model.

In this example, we have an autosurface of a bottom of a bottle. What if the scan of the bottom of the bottle isn’t flat? Well then our autosurface of the bottom of the bottle may not be flat either.

Using the rewrap command, we can extend the mesh in a natural way, create our autosurfaced solid model, then create a perfectly flat surface.

We can also change the height of the bottle by using a different cutting plane!

More Examples…

We’ll be posting the final example of how this command can be applied soon! If you missed the first example, check it out here!.

We all know that the Rewrap command is useful for interpolating mesh data as well as smoothing noisy data. If you don’t, press The F1 Key.

We’ll take a look at a few examples of how we can apply this useful command.  Example #1 is below, keep an eye out for more examples which will be posted soon!

Example #1

Defeature complex features: Want to remove a feature from your scan and fill the space in naturally? If its as simple as a bump or lettering on a smooth area, use the Defeature command. But if the feature or its location is a bit more complex, the Rewrap command can help. Just delete the area and run Rewrap. Be sure to have “Extend Boundaries” checked!

More Examples…

We’ll be posting more examples of how this command can be applied soon!

XOR/XOV/XOS 32-bit versions can use a maximum of 2GB (by default) or optionally 3GB. The 64-bit versions can theoretically use an “unlimited” amount of memory that is available by Windows.

So generally speaking, the memory limit of Rapidform depends on the memory limit of Windows.

Windows XP 32-bit is restricted to a total of 4 GB, which is, by default, equally divided between Kernel and application usage. Using the /3GB switch in the boot.ini file forces Windows to limit the kernel to the upper 1GB and provides up to 3GB for applications. Windows XP x64 can support much more memory. The theoretical memory limit that a 64-bit computer can address is about 16 exabytes (16 billion gigabytes), Windows XP x64 is currently limited to 128 GB of physical memory and 8 TB of virtual memory. In the future this limit will be increased as hardware capabilities improve.
————————————————————————–
2^32 = 4,294,967,296 bytes
4,294,967,296 / (1,024 x 1,024) = 4,096 MB = 4GB (gigabytes)

2^64 = 18,446,744,073,709,551,616 bytes
18,446,744,073,709,551,616 / (1,024 x 1,024) = 16EB (exabytes)
————————————————————————–

See http://msdn.microsoft.com/en-us/library/aa366778.aspx for more info on memory limitations for each Windows OS version.