Creating Hollow Objects
When printing a 3D model with Shapeways in our Detail Plastics, FUD/FD, Full Color Sandstone, Steel and Cast Metals, your print’s cost is calculated by two factors: Material Used and Labor.
To help optimize the price for material used, we’ll be reviewing in this tutorial how to hollow your model and create escape holes.
1. Consider the Material
First, we want to review the material guidelines of the material you are looking to print in. The key factors you’ll be looking out for is the material’s Minimum Supported Wall Thickness and Minimum Diameter for Escape Holes.
The material guidelines are designed based on the unique production process and physical traits for each material. For example, Full Color Sandstone requires a minimum supported wall thickness of 2mm while our Platinum requires 0.8mm
Therefore designing with material in mind, can help you reach the best printing results.
2. How to Hollow Your Model
We’ll be looking at a cube to demonstrate the general process of creating a hollow model.
In a traditional 3D application, this cube will appear to consist of only six faces with empty space in between. In 3D printing however, this represents a solid volume.
One approach to make this cube hollow is to extrude the outer surface inwards, creating a scaled down version inside the original box.
Pro-tip: For more complex shapes, simply scaling the model inwards may not always give you the correct results. To help get the results you need, you may need to do some manual fixing or use a different tool in your software.
Creating Escape Holes
Whenever a hollow model is being printed, the solidified area is surrounded by support material. When we remove the hollow model from the printers for cleaning, the support material inside your model needs a hole to escape.
There are several ways to create an escape hole. As an example, in this video we go step-by-step demonstrating how we prepare an escape hole for a model to be printed in Full Color Sandstone, and designer Ryan Kittleson discusses the benefits.
Pro-tip: By hollowing your object and creating an escape hole, the number of polygons in your model will increase. Note that the inside level of detail does not need to match the outside. Therefore, you can optimize your poly count by lowering the number of polygons inside your model.
Understanding Material Costing
For more tips on how to best optimize your file for low cost printing, visit our Design for Low Cost 3D Printing Tutorial for Detailed Plastics, FUD/FD, Full Color Sandstone and Metals.
Of course if you have any unanswered questions, please feel free to contact us.
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