Success Blog
By Mike Tsang • Mar 28th, 2010 • Category: Intermediate, Tech Tips, XOR, XOS
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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.
By Mike Tsang • Mar 22nd, 2010 • Category: Novice, Tech Tips, XOR, XOS
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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.
By Tom Charron • Feb 28th, 2010 • Category: Application Stories, Uncategorized
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Today we heard about a great use case for reverse engineering from some Rapidform XOR users in Germany:
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.
By Rob Liebert • Nov 2nd, 2009 • Category: Intermediate, Self-paced Learning, Tech Tips
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If you’ve ever had to manufacture a really complex, organic shape, you may have wanted to split the model along a parting line for machining. Well, this can be a very tough job without a very powerful tool, plus a little guidance. Luckily, we are talking about Rapidform here, so “check” on the powerful tool. As for the guidance, here’s a tutorial that one of our favorite customers has used repeatedly to split some of the most difficult meshes out there.
By the way, this tutorial was written with the simplified RapidWorks interface in mind. That said, all the instructions here also apply to Rapidform XOR, but the commands may be in a different place than we describe here. Anyway, without further ado, here is our guide to trimming complex meshes…
Parting Lines 101:
How to Get Those Pesky Meshes to Trim
1. Run the Healing Wizard to get rid of all defects in the mesh. Optionally, run it a second time to
iron out any remaining defects.
2. Perform a Global Remesh, keeping the default settings. Check the box “Make clean and
manifold solid mesh” if the mesh encloses a volume (i.e. is not just a surface shell).
3. Accept the edits to the mesh at this point.
4. Create/edit a parting line as a 3D Mesh Sketch. Make sure the curve is a closed loop (indicated
by a red dot where the start and end points join together).
5. Rebuild the parting line with a very tight tolerance. Optionally, split the curve into several
smaller pieces and then rebuild all of them with a tighter tolerance. See the two pictures below:
6. Copy the mesh and paste it at the bottom of the Feature Tree. Edit this new copied mesh.
7. Try to trim the mesh using the “By Curve” method, and choose “Rearrange Poly-Vertices” at the
bottom of the command tool.
8. If this doesn’t work, or you get a message like the one below, you need to tighten the tolerance
on the parting line curve even more. Exit out of mesh-editing mode, then edit the 3D Mesh
Sketch of the parting line.
9. Select the whole parting line (i.e. all the segments that make up the closed loop). It’s time to try
some edits that will help the trim run smoothly:
– a. If you did not split the curve before, do so now by choosing the Split command with the
“Pick Points” option and clicking on several points around the curve.
– b. Double-check that the curve is closed by identifying a red point somewhere on the
curve.
– c. In the “Rebuild” tab at the top of the screen, make the allowable deviation (of the curve
from the mesh) smaller by a factor of 10. You should notice that the number of control
points increases drastically to meet the stricter tolerance.
Accept the changes to this 3D Mesh Sketch.
10. Edit the copied mesh again. Trimming should now work for you. If not, repeat steps 9 and 10
until it does trim well.
Choose both the inner and outer portions as “remaining regions,” and accept the command.
11. Choose the “Flood Fill” selection tool at the bottom left of the screen (i.e. the paint bucket).
Hide all meshes besides the one you are editing, and then click on one side of the active mesh.
When you have selected one half of the trimmed mesh using the Fill tool, hit Crl+C or select
Edit.Copy. Now accept the changes to the mesh and hit Ctrl+V or select Edit.Paste outside of
any mode to paste a new mesh into the Feature Tree. This new mesh is made up of only those
polyfaces that were selected before, so it is one half of our desired result.
12. Edit the complete, trimmed mesh once again. Choose the Flood Fill selection filter, and use it to
select the other half of the trimmed/split mesh. Copy this portion just as you did in step 12
above, then exit out of the mesh editing mode. Outside of any particular editing mode, paste
the selected polyfaces as a 2nd (or 3rd) new mesh in the Feature Tree. You now have both pieces
split along the same curve and saved as individual meshes. Save the RapidWorks project, export
your split meshes and continue with your overall workflow! Here is a shot of the final result:
Happy mold making!
By Mike Tsang • Oct 26th, 2009 • Category: By Level, By Product, Intermediate, Self-paced Learning, Success Blog, Tech Tips, XOR, XOS
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The Rewrap Command (part 3)
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!
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