CATEGORY: 3D Printing

A Quick Overview of 3D Printing

In the 3D printing world, the main focus is printing geometry with color. That means that other things used in rendering such as lights, special effects, cameras, etc; are ignored.

The 3D Systems printer comes with proprietary software called 3DPrint. 3DPrint is where you import your various types of files including (.stl, .3ds, .wrl). The 3DPrint software can tell you if a model has reversed faces and show you a 2D view of each layer that will be printed. The program can also scale, rotate, position, and even mirror parts inside the build chamber. The size of the build chamber depends on the model of the 3D Systems printer that you are using.

3D Systems’ machines range from 8” long (X-axis) by 10” wide (Y-axis) by 8” deep (Z-axis) with the ProJet 460 and 15” long (X-axis) by 10” wide (Y-axis) by 8” deep (Z-axis) with the ProJet 660. The average build time for parts is around 1 hour per every inch built in the Z-axis.

General Information

1) Three-Dimensional geometry used for 3D printing can be generated in any 3D modeling application.

Common applications are Autodesk’s 3ds Max, AutoCAD, Revit,  Fusion 360; and Rhino from McNeel.

2) All geometry to be 3D printed must be in three-dimensions. Any two-dimensional geometry cannot be processed by the machine’s software or interpreted by the 3D printer.

3) One way to check your geometry accuracy is viewing your STL file in an STL viewer. Some programs to look into are Netfabb and Meshmixer by Autodesk.

4) All three-dimensional geometry must consist of closed volumes.

1. An easy way to test for this is by checking the model’s volume. If the CAD software can calculate a volume it’s generally because the model consists of closed volumes.
2. In Netfabb you can run one of the repair scripts and that will attempt to automatically repair open contours and edges. Usually it is able to take care of any issues without much user input but sometimes a manual repair is required. Sometimes the changes may need to happen in the native application.

5) Ideally all geometries are unified to create a single object.

6) It is standard procedure to share screenshots, conduct webinars, and exchange emails to ensure proper interpretation of your file and setting customer expectations.

Minimum Thicknesses

1) Thicknesses needed for accurate and high-quality 3D printing may range based on the specific geometry.

2) The purpose of having minimum thicknesses in the file is to ensure that the printed output is accurate to the file’s geometry and meets expectations of quality.

3) Meeting minimum thicknesses can be a challenge if the model was not modeled for 3D printing. Especially in architecture, scaling to such a large degree causes many components to surpass the machine limitations.

4) The minimum thickness is also depending on the type of 3D Printer being used. There are high-resolution 3D printers and low-resolution 3D printers.

5) Exceeding the machine’s resolution capabilities may result in lost geometry.

6) As a general guide we use 0.04” as the minimum thickness for walls, beams, pillars, etc. But it is height dependent.

1. Example: 1/2” tall pillar at model scale would require a minimum thickness of 0.04”. Increasing the thickness, however, to 0.06” or 0.08” would produce a smoother and more accurate pillar. (Since the look of the model is critical to communicating design intent we understand that both thinness and smoothness are very important. In some cases we recommend extruding the geometry to the inside of the model, somewhat hiding the ‘thickening’. The resulting pillar maybe 0.04” (x) and 0.06 (y) and create a smooth and visually accurate model.)
2. If however, the pillar is 2 inches in height, a thickness of 0.1” may be needed to be accurately produced since it’s much larger it would need more ‘structure’ to keep it strong. In summary when we’re talking about fine, thin geometry, the larger or taller the geometry, the thicker it will likely need to be.

Exporting Guidelines

1) Once you have checked that your file consists of only three-dimensional closed volumes you are ready to export your file.

2) Translate your model to the HOME axis of 0,0,0

3) Scale your file to the final print output size

4) Change the units in your application to either inches or millimeters. When files are transferred between 3D applications the only information that transfers is the unit numbers, not the unit measurement, such as feet, inches, meter, etc. Thus, after you scale, if you change your units to inches then it becomes a breeze to transfer files between 3D applications.

5) Exporting an STL file usually involves the ‘Export’ or ‘Save As’ function. STL is the most common file format for use in 3D printing. Your three-dimensional design will be converted to a three-dimensional triangulated polygon mesh, made up entirely of triangles. STL stands for Stereolithography

6) BIM data, file history, XML data, or any other information associated with the model that was contained in the native application will not be available in STL format. An STL file contains only an X, Y, and Z coordinate for each point that makes up the individual triangles. The points are based on the universal world coordinate system.

7) If your application does not export to STL the next preferred file formats are .3ds and .dwg. This format can be brought into almost any 3D CAD application and exported to STL from there.

8) After you’ve exported your file it is good practice to review the converted STL file in an STL viewer. You can view the STL in many 3D modeling applications but an STL viewer is sometimes easier to see where errors may be located.

Below is a picture of ideal printing for the 2D layers of a print. These are the layers that you can see in the 2D view and they show what is going to be printed on a specific layer.

Created by: 3D Systems, NRI 3DLab, Andrew Esquivel Peak Solutions, DMC London; The Bartlett School of Architecture / CADCAM and the Bartlett workshop, University of Penn School of Design, McNeel (Rhino), CADSpan, ZCorporation, and Microsol Resources.

If you have any questions or need advice on 3D printing, feel free to reach out to our team at 3dprinting@microsolresources.com.

The release of Rhino 7 is the most significant in the 30 years since Rhinoceros3D was first introduced. At its heart, RhinoCommon offers a powerful geometry engine with high mathematical accuracy, and with new features like SubD modeling and Clash Detection, it is only getting better.

If you haven’t already purchased a license of Rhino 7, I hope that by the end of this article you are convinced that it provides huge value out-of-the-box and great potential in the future.

Rhino3d.com/7/new/ lists all of the new features and capabilities of Rhino 7. For ease of navigating, links to some of the best features are listed below:

SubD Modeling

Explore organic shapes quickly and easily

Rhino.Inside Revit (beta)

Rhino 7 can now be used as a plugin for Autodesk Revit, expanding the possibilities for both programs. More info below…

Quad ReMesh

Quickly create a Quad Mesh from existing geometries, including SubDs

Clash Detection

Detect and resolve clashes quickly.

Package Manager

Installing and managing plugins for Rhino+GH is now easier than ever, right from Rhino itself!

Grasshopper Player

Grasshopper was packaged as part of Rhino 6, and now with the GH Player, Plugins can be built to receive User Defined Inputs without the need to open and run the Grasshopper definition.

Presentation Tools and Display Pipeline

• • The Render Engine received a major update
  • Raytraced Viewport allows for interactive rendering
  • PBR Materials and Multi-threading with OpenGL, optimized with certain hardware

Documentation

From Enhanced Text Fields that work with Formulas to Layout Management tools, it is easier than ever to document your designs

New Commands in Rhino 7

A full list of all of the new Commands that are available. For quick reference and similar to past versions, there is a tab called New in V7 which has some of the best new commands.

In addition to all of these new and enhanced features that come with Rhino 7, there is much effort afoot to bring the capabilities of Rhino into almost any environment (Rhino.Inside).

Development Platform

The foundations of Rhino are ready for broader and deeper applications of its capabilities. As plugins for Rhino have been developed over the years, it has spurred a thriving developer community with advanced tools for data and geometry manipulation.

In Version 6, Rhino was made into a Dynamic Link Library (DLL), which allowed for a couple of things to happen in the development of Rhino 7:

A. Plugins (particularly C++) developed for Rhino 6 will work with Rhino 7 and possibly later versions without breaking the SDK.

1. For scripters, this provides a more solid footing for the development and support that would be necessary for plugins.
2. For Firms and BIM/VDC Managers, this gives more long-term reliability in the tools that are incorporated into certain workflows

B. Rhino can be run as a plugin within other applications

1. Standalone Console Apps / .NET Web Servers (Rhino Compute)
2. CPython
3. Revit (Rhino.Inside.Revit)

Rhino Compute lets Rhino run on a .NET Web Server, effectively bringing Rhino to the cloud. Startups such as Hypar are working to bring Grasshopper scripting and much more to the web browser, allowing for design input to come from anyone, anywhere.

The most popular flavor of the Rhino.Inside technology is Rhino.Inside.Revit (beta, free), which has effectively made Rhino 7 the largest possible plugin for Revit. Not only is it the full version of Rhino running within Revit’s memory space, but all of the plugins are compatible with Rhino 7 as well. Plugins that had been developed for Rhino 6 remain compatible, so the functionality that is part of many scripts and workflows can endure.

There are new Grasshopper Components found in V7, with the majority available within Rhino.Inside.Revit, in the Revit Tab.

For more information on Rhino.Inside.Revit Technology, please refer to our other blog posts and our Microsol Resources’ Youtube Channel for additional resources and webinar recordings.

Rhino 7 provides a framework with minimal barriers to entry. From the lone wolf coder to the multi-national firm, Rhino 7 can be very powerful if leveraged properly. A great conversation with Steve Baer, Luis Fraguada, and Will Pearson of Robert McNeel & Associates can be found on ProArchitect’s Youtube page. They discuss the rationale and forward-thinking concepts behind Rhino 7 and the Rhino.Inside technology, but for the most part, opine on Rhino Compute.

Want to upgrade to Rhino 7 or have any questions about any of the New Features? Feel free to contact us at rhino@microsolresources.com. 

There’s an old saying that I’m sure you’ve heard that goes “you won’t know until you try”. While it’s one of those phrases that’s been around long before computers were in every office, it remains modern enough to be very relevant to working with software. I found myself thinking about this phrase when a client asked if they could have a Civil 3D surface printed on our 3D Printer, a 3D Systems CJP Project 660Pro.

It may sound obvious, but the only prerequisite for printing anything in 3D is that the object has a width, depth, and height. A Civil 3D surface object, while made up of X, Y, and Z points, is only a two-dimensional object since it has no thickness. The first hurdle would then be to add some “thickness” or height to that surface to make it printable.

If you are a Civil 3D user you may think, “well that’s easy, just use the Extract Solids from Surface”. And while that is exactly what crossed my mind when I started thinking about how to print a Civil 3D surface, it turns out that the Extract Solids from Surface does not work for very complex geometries. This command is great for extracting out solids from corridors and smaller surfaces, but it couldn’t generate a solid for a heavily graded 70-acre subdivision with 100’ of elevation difference between its low and high points.

As I didn’t have rights to use the surface described above when writing this blog, I am instead using another surface to illustrate the steps. For all intents and purposes, these steps will work for any surface.

Exporting Civil 3D Data for 3ds Max

Met with failure, I turned to 3ds Max, the most powerful geometry editing software in the AEC Collection. I had many options to choose from when importing the Civil 3D surface into 3ds Max, but I narrowed it down to two options.

The first option would use Civil View to exchange Civil 3D object data with 3ds Max using a VSP3D file. The second option is to export a LANDXML file from Civil 3D and then import that file into 3ds Max.

I ended up choosing the latter option since it automatically generated polygons in the various HIDE boundaries found on the Civil 3D surface I was using. While I lost a marginal amount of fidelity from the original surface, using LANDXML created a gapless surface which we preferred for the 3D Print.

Exporting a LANDXML file from Civil 3D is as easy as right-clicking the surface in the Prospector and selecting Export LandXML… Importing the LANDXML file into 3ds Max is equally simple; click on the File menu, choose Import and select the LANDXML file. You should uncheck Smooth Surface in the Object Creation Options to preserve the Civil 3D surface geometry.

Creating a watertight model

Unlike the Extract Solids from Surface command in Civil 3D, I simply had to create a watertight poly surface or mesh in 3ds Max. A watertight model is defined as an object that doesn’t have any naked edges. McNeel’s website makes a great analogy when defining a watertight object; “another way to understand a solid is to see it as a balloon. If there is even a pin prick size hole, it will deflate. Thus it is not air/watertight, not volumetric. A solid is a volume. A solid is its outer surfaces, once they are completely joined”

The LANDXML import provides me with a editable mesh in 3ds Max. To manipulate the geometries in the mesh to create the watertight solid I previously mentioned, follow these steps:

• Select the Editable Mesh and choose the Element sub-object levels in the modifier stack
• Click on any part of the surface and you will see the entire mesh highlight
• In the Edit Geometry rollout enter in an Extrude value; I will use 500’
• Switch the to the Edge sub-object level and press the Select Open Edges button in the Edit Geometry rollout
• With the open edges selected, toggle the Top view and select View Align from the Edit Geometry rollout. This will flatten the edges to the same Z value
• Choose the Face sub-object level and drawing a Crossing Selection through the recently extruded faces
• Select the Detach button from the Edit Geometry rollout to create new object from those faces
• De-select the original mesh and select the detached mesh
• Right-click and choose Convert To: Convert to Editable Poly from the Transform Quad
• Select the Editable Poly object, activate its Border sub-object level, and select the open border
• From the Graphite Modeling Tools, select Cap Poly from the Geometry (All) Panel in the Modeling ribbon
• Activate its Polygon sub-object level and select the bottom polygon cap
• Press the W key to activate the Move gizmo and raise the Polygon along the Z axis to the desired height
• Deselect all sub-object levels, select the Editable Poly
• Right-click and choose Convert To: Convert to Editable Mesh from the Transform Quad
• De-select the detached mesh and select the original mesh
• Select Attach from the Edit Geometry rollout
• Choose the detached mesh to join it to the original mesh creating a watertight mesh

Despite the extensive list of steps, the process is straightforward if you are familiar with 3ds Max. The video below illustrates all these steps to make it easier to follow along.

Create a file for 3D Printing

Once the geometry has been edited to be watertight, export the geometry to an STL (STereoLithography) file. In order to send our 3D print jobs, we use an application called 3D Sprint. 3D Sprint can import the STL, check for any geometry errors, and scale the model so it can be printed. The screenshot below shows the 3ds Max geometry ready to be printed.