3D Printing Mesh Preparation

If you have not read our Design Approaches and Design Guidelines, we strongly recommend that you go through those first as they cover all the fundamental aspects of 3D Printing concept and implementation.

Overview

Now you should have a clear outcome in mind and a model prepared for 3D Printing, this guide will take you through exporting models to the 3D Printing Software.

The following content is based on a Rhino 3D Workflow, but you can adapt it to your preferred CAD software.

Model Preparation

Virtual Build Plate Layout

Draw a wireframe to simulate the build plate/volume. For the Replicator+, the build area is 295x195x165mm and for the Z18, it is 305x305x457mm.

Setting a buildplate in Rhino. Always double check that the meshes are aligned to the same bottom plane.

Model Position and Splitting

Move geometry to as close to the origin as possible to prevent any numerical precision errors during the slicing process.

If geometry does not fit in the build volume, will lead to too many support structures, or you you need to guarantee a certain orientation of printing, you may need to consider splitting the model:

pageSplit Models & Joints

Arranging your Model

Depending on your workflow, you can:

Arrange Model Later	Arrange Model Now
Export all geometry as individual files. Can be ideal if you want more flexibility in laying out build plates. Makerbot Print or CloudPrint provides an easier workflow for geometry with lots of angled surfaces.	Export geometry in groups It is generally faster and more precise to arrange your prints in Rhino. Controlling scale and wall thickness of objects is much better in Rhino.
Please skip to the next step, Assessment	Please continue on with this step

Orienting Geometry

1. Rotate can be used OR

2. Orient3Pt can be used to rotate more complex geometry based on the face of the model.

   1. Select the geometry to orient

   2. Pick 3 points that define the face on the model

   3. Pick 3 points on the standard work plane to orient it flat.

Aligning Geometry

Use the Align command to align all your models to the same plane (it could be any plane). This command treats grouped models as a single entity so ungroup first if necessary.

1. Change to an elevation view (Front, Back, Left, Right).

2. Select your models and execute the Align command.

3. In the Align command, select the Bottom sub-command.

4. Your models will snap to a common bottom plane. Drag your mouse around to choose the location of this plane and left click to confirm.

Select your models and run the align command.

Assessment

Now you need to ensure that your model consists only of closed polysurface/extrusion/meshes, this is especially important if you have split your model up.

In Rhino, the ShowEdges command can be used to highlight naked or non-manifold edges. The Object Type in the Properties box is also a good way to quickly check if an object is closed or open.

ShowEdges and Object Type

If you have any naked edges or non-manifold edges, clicking Zoom in the dialogue box will center your viewport in the problematic area so that you can attempt to fix it.

Zoom into naked edges to quickly identify problem areas.

Troubleshooting Geometry

After you have identified problematic areas, depending on your workflow, you can attempt the following:

Remember: Rhino is much more adept and better at fixing errors in the modelling (NURBS geometry) stage instead of meshes. Always try to resolve problems there.

NURBS

Geometry can be rebuilt if you are using a NURBS workflow - operations that commonly result in problematic geometry are Boolean operations and complex surface generation so look out for those areas. Alternatively, you can Mesh your model first (the next step) and attempt to fix it through the Mesh workflow.

Mesh

While not optimal, there are a few more options rather than rebuilding geometry. Refer to our extended Mesh Troubleshooting guide:

pageRepairing Meshes

Meshing

While you can directly export your polysurfaces as meshes using the Export command as well, note that it skips the step where you can double check if your mesh has errors. Therefore, use with caution.

If you have been working with NURBs, use the Mesh command to generate meshed geometry. Meshes are required for 3D Printing.

1. Polygon Count Slider: Increasing the polygon count will allow it to better represent curved surfaces. However, this will greatly increase file sizes and slicing times in the next phase. Aim for the least amount of detail as required and adjust as required.

2. Detailed Controls can be used to fine tune the mesh as generation as well. Refer to Rhino documentation for a full breakdown.

It is good practice to check your mesh again with the Check command. Doing so will let you identify any problems and allow you to quickly go back to your polysurfaces and models to fix them.

Remember: Rhino is much more adept and better at fixing errors in the modelling (NURBS geometry) stage instead of meshes. Always try to resolve problems there.

Exporting

You can now use the Export command to create .stl files.

When your geometry is ready to be exported, you can now use the Export command to create an .stl FILE.

Run the Export command.

When you execute the Export command, a dialogue box appears with .stl export options. It is recommended to stick to the defaults.

Default .stl export options.

You are now ready to proceed to the next phase! But before you do, please note our submission requirements:

SUBMISSION As part of the Request submission process, you will be asked to provide ONE .STL file

of all your geometries so we can double-check for you, you can do that now with the following naming convention: (Filename)_(Version).stl e.g. house_v3.stl