Follow Along: Periodic Lattice on Faces

In this lesson, we’ll learn how to use meshes and CAD faces to create cell maps and generate periodic lates for lightweighting and texturing. Begin by downloading the starter file below. As we saw in the last lesson, if we isolate this part using “I” and zoom using “Z”, we have a two-part CAD bracket that we’re starting with. Under the Utilities tab, we’ll again add two Implicit Body From CAD Body blocks to our notebook.

We’ll pull in our inner body and our outer body. Isolate using “I” to see which one we’re working with and right-click to make each a variable. Again, we’ll use a Boolean Union block under the modeling section and Union both of these variables to create a third variable called “entire part”. I’ll collapse these new variables with the space bar and move on to our Unit Cells section. Here, I’ll create two different unit cells: a walled TPMS and a graph unit cell. Under my Lattices tab, I’ll pull in a Graph Unit Cell as well as a Walled TPMS Unit Cell. For our TPMS, I’ll choose a split P unit cell, and for our graph, I’ll choose a square honeycomb. I’ll make these into variables and call them “graph” and “TPMS”. I’ll collapse using the space bar and move on to our Cell Map section.

First, I’ll want to lightweight our inner body using our split P wall TPMS unit cell, so I’ll have to create a cell map across this inner body. I’ll add a Cell Map block, Rectangular Cell Map, and make our volume inner body with a cell size of 35x 35x 35 mm. I see that we’ve created this cell map across this body. Notice that here we’re viewing the full map, but we can also navigate the map using our unit cell viewer. Each of these boxes is where one of these unit cells will go. I’ll right-click to make this cell map a variable called “rectangular cell map”.

In addition to creating cell maps across implicit bodies, we can also create them on CAD faces. I’ll isolate my CAD part using “I”, and under Cell Maps, I’ll add a Cell Map From CAD Face block. Let’s say we wanted to add a periodic lattice to this CAD face. I would click the face I wanted to select, right-click, and create a CAD face variable. I could then pull this variable or its contents in as my CAD face. Then I could select a UVW count. Here, I’ll make it 10, 3, 1, and select my height. I’ll make my height -1 since I want to texture this face and remove material from our periodic lattice that we’re creating. Zooming in, we see the cell map that we’ve created from this CAD face. With our UVW guide, we can see exactly what’s happening with our local coordinates. In the U direction along this red axis, we have 10 evenly based cells. Across our green V-axis, we have three cells, and along our W axis, we have only one cell. I’ll right-click to make this a variable and call it “CAD cell map”.

In addition to creating cell maps across a CAD face, we can also create them from quad meshes. I’ll add a Cell Map block, Cell Map From Quad Mesh, and we’ll need to create a quadrangular mesh of the faces that we want to cell map across. I’ll start by isolating my part using the hotkey “I”, and then I’ll create a CAD face list of the faces that I want to texture. Holding the Control key, I can click each face that I want to texture, and I’ll click all of these CAD faces around the outside edges of our part. I’ll right-click and create a CAD face list variable.

I’ll then add a block, Stitch Adjacent CAD Faces, and I can delete out this pre-populated CAD face list and pull in our variable that we’ve created. If I isolate using “I”, I’ve created this CAD body. Next, under our Utilities section and Conversion, I’ll add a Mesh From CAD Body block and pull in our CAD body. Isolating using “I”, I see that we’ve created this mesh. Next, I’ll quadrangulate this mesh using the context search. To do so, I’ll add a Quadrangulate Mesh block that will be this parent block, and I see that my mesh has automatically been nested into this Quadrangulate Mesh block. Next, we’ll add this quadrangulate mesh into our Cell Map From Quad Mesh block. We can add a height of -1 to remove one mm of material once we make our periodic lattice, and we’ll add one as our layer count. If we view our cell map, we see that it’s created this cell map on all of the edges of our quad mesh. Let’s make our target count a variable. If we change this down to 500 from 2,000, we see that our cell map updates to have larger cells and a lower cell count. Let’s make this cell map from quad mesh a variable, right-clicking, making it a variable, and calling it “mesh cell map”.

We’ll collapse all of our variables, and now we can move on to creating our periodic lattices and our final part. Let’s start by lightweighting our inner body. Under our Lattices tab, we’ll add a Periodic Lattice, and we’ll pull in our TPMS unit cell as well as our rectangular cell map across our inner body. We’ll set a thickness of 5 mm and create this internal split P periodic lattice. I’ll isolate this and make it a variable called “inner lattice”.

Now, we’ll add a Periodic Lattice block for our texturing, and our unit cell will be this graph unit cell that we created. Let’s make our cell map our CAD cell map from before, and we’ll make our thickness 1 mm. If I view this periodic lattice in relation to our entire part, I see that we’ve created this 3D structure across the CAD face that we selected earlier. I’ll right-click to make this a variable and call it “texture”. This will be the substance that we remove from this face to create a debossed texture across our body.

Now, we’ll put the final part together. I’ll add a Boolean Intersect block from our Modeling tab, and I’ll intersect our inner lattice with our inner body. I’ll then add a Boolean Union block, and I’ll Union this intersect with our outer body. I’ll add a blend radius of 5 mm, and then I’ll have to trim away any of this excess material. I’ll use another Boolean Intersect block to do so. I’ll intersect this part with our entire part, and now we have clean edges across our entire part.

Finally, to remove the texture, I’ll add a Boolean Subtract block and pull in our Boolean intersect as our primary body and our texture as our subtraction. If I right-click and make this a variable called “final part” and collapse all of our variables, I can view this final part that’s lightweighted across the inner body and textured across our CAD face where we’ve created our cell map. If instead of this cell map that we created across our CAD face we wanted to texture the entire mesh cell map that we created earlier, we could pull our mesh cell map into our texture variable, and viewing our final part, we’ve textured all of the outer sides of the outer bracket.