In my article about „3D Lattice Structure Design for Additive Manufacturing“, I showed you how to create 3D lattice structures in the 3D volume of your designs so you could create stiff volumes with drastically less weight and production costs. In this article, I am going to focus on how to generate those lattice gradients for Additive Manufacturing with the free and open source tool Blender 3D.
Creating 3D Lattice Structure designs for Additive Manufacturing
3D Design for Lattice Gradients
First of all you need a 3D mesh or an STL file to define the form of your resulting lattice structure. In the video I’m using a basic 3D Mesh.
If your mesh is of a very high resolution, you should use the Decimate Modifier to reduce the mesh size. The mesh size is ideally the size of the holes you would like to have in your lattice structure.
1. Wireframe modifier to create the Lattice Structure
After reducing the mesh size with the Decimate Modifier , we can apply the Wireframe Modifier feature that we use as a lattice generator to create the lattice structure on our mesh. You can adapt the thickness of the lattice, check the boundary to create wireframes on mesh island boundaries and ideally uncheck even thickness to avoid errors.
If you want to learn more about how to create the lattice structure using the Wireframe Modifier I explain it in more detail in the article „Creating Basic Lattice Structures with Blender 3d“
2. Make the lattice smoother
To be able to get smoother transitions and thicker connections I used the Subdivision Surface Modifier. This smoothes out the lattice structure and leaves you with a more organic design. You can control the form with the number of subdivisions adapting the viewport.
3. Create a Vertex Group
To apply different thicknesses to the lattice structure you have to create a vertex group that is influenced by the weight factor. Go into Edit Mode, and put the complete mesh in the group in order to define the strength via the weight paint. If you only would like to influence a certain area of the mesh, without a thickness gradient, you would only put that area in the vertex group.
4. Color Paint the lattice thickness
Using the Weight Paint mode and the tool Gradient Paint with Alt, you can create a gradient color and therefore thickness gradient over the whole part. You can also freely paint areas with more thickness with red and the minimal thickness with dark blue.
Afterwards select the vertex group in the wireframe modifier and you should see your painting represented in the thickness of your lattice structure.
5. Adapt Weight Factor and Lattice Thickness
If you set the vertex group in the Decimate modifier, you can define the hollow density of your lattice. You can also check the triangulate option to keep the result as a triangulated geometry.
If you set the vertex group in the wireframe modifier, you can play with the thickness and control the strength or importance of your paintings. Factor „0“ means 100% importance and therefore zero thickness at the dark blue area. The red area has the same thickness as the one set at the wireframe modifier. Factor „100“ means the painting has zero importance and therefore the whole part has the thickness set in the modifier, no matter the painting.
Finally, adapt the Subdivision Modifier to create smoother connections in the lattice structure. Keep in mind the minimal thickness of the 3D printing process you are using. Always adapt the design to the additive manufacturing technology and used material.
After applying the wireframe and subdivision modifier, I suggest you also use the Decimate Modifier to reduce the final file size of your STL file. The typical stl-size shouldn’t exceed 50Mb. Lattice structures with below 1mm thickness don’t need a lot of mesh resolution, since most additive manufacturing processes have a minimal resolution of 0.4mm.
I hope this quick overview on how to create 3D lattice gradient structures is helpful for you. Please feel free to comment or send me your creations and ask me any questions!
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