Polygon Reduction with Meshlab

There's a limit to the complexity of objects that you can upload to Shapeways: they can have no more than 1 million polygons. More polygons than that quickly become too much work for our servers and printers to handle.

Some tools like ZBrush can quickly create a high polycount, so its easy to run into this limit. Fortunately there's a solution known as polygon reduction (also known as mesh decimation). Chances are that your 3D application already has this built-in, otherwise the open source tool MeshLab offers an excellent alternative. MeshLab is available for Windows, OSX and Linux.

The picture below shows the results of a test I did with a small toy car model that had 480,000 faces. Down to 120,000 faces, the difference in quality is hardly noticeable. Below that, you'll see the model becoming rougher and rougher (click on the image to see the high-res version):

Let's get started!

If you haven't already done so, please download and install MeshLab and import your model.

From the menu, select Filters > Remeshing, simplification and construction > Quadratic Edge Collapse Detection. If your model is textured, there is also an option (with texture) that will do a good job at keeping your textures positioned properly. A panel with a few options will show up. You can click on the 'Help' button to get extra information about the available options, but that didn't answer all my questions so I checked with the creator of MeshLab, Peolo Cignoni.

Here are the option settings we believe to be optimal:

Target number of faces - Self explanatory

Quality threshold: 1. Enter a value between 0 and 1 here; the higher the value the harder MeshLab tries to stick to your original model's shape. The documentation isn't clear on what the consequence of using a higher value is - my impression is that it's slightly slower than low values, so I happily used a value of 1 with great results.

Paolo's comment: 'Quality threshold affects the simplification penalizing bad shaped faces. To approximate accurately the original shape only with well shaped triangles you require a higher number of faces with respect to allowing more freedom in the final triangle shape. The value is in the range [0..1]: 0 accept any kind of face (no penalties), 0.5 penalize faces with quality < 0.5, proportionally to their shape".

Preserve Boundary of the Mesh: Yes. Paolo's comment: 'The simplification process tries not to destroy mesh boundaries, e.g. exposed edges of the mesh are left untouched. This parameter has no effect on watertight meshes.'

Preserve Normal: Yes. Select this to stop MeshLab from accidentally flipping the face normals. Paolo's comment: 'Try to avoid face flipping effects and try to preserve the original orientation of the surface. The only drawback of enabling it is a slight increase in the processing times. On by default.'

If you DO run into inverted normals issues when uploading, try reorienting the normals with the option Filter > Normals, Curvature and Orientation > Re-Orient all faces coherently (note that this will only work for manifold objects).

Optimal position of simplified vertices: Yes. Paolo's comment: 'When collapsing an edge the chosen vertex position minimizes the current estimated error. If disabled, the edges are collapsed onto one of the two vertices and the vertices of the final mesh are a subset of the original mesh. It’s on by default.'

Planar simplification: Yes. Paolo's comment: 'Add additional simplification constraints that try to preserve the current shape of the triangles. It can greatly improve the quality of the shape of the final triangles on perfectly planar portions of the mesh. Like the quality threshold it affects the accuracy/complexity ratio. Off by default because it is very useful only in particular situations like when you have perfectly flat areas finely tessellated.’'

http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab

3D-Printed Surfboards Are Custom Designed for Each Surfer

Surfing pros and novices alike will be intrigued by an ongoing Kickstarter project from a company that wants to design 3D-printed custom boards based on actual data derived from riding in the water.

Chicago-based MADE Boards is trying to raise $450,000 on Kickstarter to further develop its sail, kite, surf, and paddle "SmartBoards." Using MADE's VOLUME mobile app for iOS and Android, customers can figure out what board is best for their own body and activity, and MADE will then custom build it.

Surfing pros and novices alike will be intrigued by an ongoing Kickstarter project from a company that wants to design 3D-printed custom boards based on actual data derived from riding in the water.

Chicago-based MADE Boards is trying to raise $450,000 on Kickstarter to further develop its sail, kite, surf, and paddle "SmartBoards." Using MADE's VOLUME mobile app for iOS and Android, customers can figure out what board is best for their own body and activity, and MADE will then custom build it.

The internal structure of the boards are 3D-printed, taking into account specific factors like shape, rigidity and how much the board curves. The board is then wrapped in bamboo underlayment and a fiberglass shell to stiffen it. MADE's founder Shanon Marks says additive manufacturing — or 3D-printing — lets the company factor in a person's geographic location, atmospheric conditions and the way the individual rides the board. Marks told Mashable their platform uses social data, performance tracking/journaling and big data to influence design.

"You look at a surfboard, you look at a sailboard and it has terabytes of data 'stored' inside of it," Marks said. "Like there's this amazing, amazing history of everything it does on the water. What if we could quantify that?" 

"Additive manufacturing really became the best way to do that because it's a direct translation from the data input that we're collecting."

Here's how MADE's process works for consumers: Download the performance-tracking VOLUME app (for Android and iOS) before you buy their equipment. Using any existing board you might have, put your phone in a waterproof case and wear it while you're riding it. Throughout various days, the app can collect insights on your performance that will be used as design influences for a new board. The app collects data like the time of day and year, but also cross-references with relevant atmospheric conditions: e.g., wind speed, wind direction, wave height, wave speed, wave direction, barometric pressure, altitude, and freshwater versus saltwater.

Using that collected atmospheric data, biometrics and aggregated social information from other VOLUME users, you'll get a suggested board that's meant to be just right for you.

Growing up windsurfing and sailing himself, Marks said MADE began out of the frustration that people pay thousands of dollars for equipment that he says isn't made for them.

"One of the unfortunate things that I witnessed in the (windsurf) industry is that there was a huge emphasis on specialization around materials and super high performance," he said. "The unfortunate part about it: That came at the expense of the consumer's wallet — like boards just got more and more and more expensive."

Marks hopes to make these sports more accessible. He also claims additive manufacturing is a win from an environmental standpoint, since 3D-printing can minimize material use.

MADE's Kickstarter campaign still has 18 days left to go and had only reached about one percent of its fundraising goal, as of Tuesday afternoon. Backers who pledge at least $799 can get a MADE kite board; $999 for a "series one" SmartBoard; $1,299 for a paddle board; and $1,499 for a sail board.

See one of Made's 3D-printed sailboards in action in this video:

Surfers: Would you buy a 3D-printed surfboard? Newbies: Would these 3D-printed boards have you riding or staying on the shore? Let us know what you think in the comments.

Images: MADE, LLC/Shanon Marks.

http://mashable.com/2013/07/17/smartboards-3d-printed-surfboards/

http://www.madeboards.com/

Microstructure Model

Goldberg Polyhedron

Goldberg Polyhedron – Bottom

Goldberg Polyhedron – Top

Goldberg Polyhedron – Side

George Hart’s model of Michael Goldberg’s polyhedron has quickly become the “Hello World” of resin printers. I tried to print a half of the model simply because it was in my test folder, not expecting it to print at all.  Surprisingly it came out reasonably well, except that the sides suffer from z-layer bleeding. Several of the holes remained filled with resin – some isopropyl alcohol and some diligent cleaning would sort that out I think. I should note that each square on the mat in the photos is 10mm across.

Failed Goldberg Polyhedron

Even the failed prints look good! Here the print failed to attach to the base and remained on the vat floor for the duration, leaving a 2D projection of the half-sphere.

Microstructure Model

Microstructure Model – Bottom

Microstructure Sphere – Partial – Top

Microstructure Sphere – Partial – Bottom

This model is again from the Functional Representation program. In my search for efficient fill algorithms I came across the work of Alexander Pasko and various colleagues, particularly a paper entitled “Procedural Function-based Spatial Microstructures” (PDF) which details exactly what I was looking for. Since then I have been attempting to recreate their findings, particularly the models with parametrised internal structure. Last week I finally was able to create the model and so of course it was one of the first things I wanted to print. The photo’s do not really do it justice – and there is still a lot of improvements to make – but I was pretty excited to print some resemblence to the model. Below is an image from a later paper, “Procedural Function-based Modelling of Volumetric Microstructures” (PDF) which shows how the model should look. The first image in the gallery above is the model I created, and the photos are of a print of the middle quarter of the sphere, and some of the structure is clearly visible. I plan to write an entire post on this subject as I think there is a lot of potential in relation to 3D printing.

Volumetric Microstructure taken from "Procedural function-based modelling of volumetric microstructures", Alexander Pasko et al.

http://garyhodgson.com/reprap/category/dlp-resin-printer/