How to 3D Print site models through SketchUp & Cura
To represent a site effectively to a client, or to provide models to the City of Sydney archive as per requirement. Other methods that could be appropriate (for representing models to clients) include creating a VR experience, producing a poster, video or similar website.
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Installing. Follow this to install the extensions necessary to follow the rest of the processes
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Cleaning. Follow this to clean your model. Cleaning your model throughout the process is recommended.
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Slicing. Follow this to slice your model up into manageable chunks for the 3D printer.
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Exporting. Follow this to export your model into a format acceptable to 3D printing software.
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Setting. Follow this to learn how to set the 3D model up for printing in the 3D printing software.
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Install SketchUp 2017:
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There are four extensions we need to download:
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TT_Lib2
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CleanUp3
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Solid Inspector2
https://extensions.sketchup.com/en/content/solid-inspector%C2%B2
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Zorro2
Note: Although this guide will go through some of the functionalities of these extensions, if you ever get stuck or want to learn more about the extensions there are some excellent video and article tutorials on the above pages.
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Open up SketchUp, select Window > Preferences, then open the Extensions tab.
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Install the extensions above in the given order.
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Import the model into SketchUp.
Note: If you’re going to do any modelling in SketchUp, leave it all in “Layer0”. Layers don’t work the same in SketchUp as they do in other programs like Rhino, instead use groups for similar functionality.
Note: DO NOT scale the geometry down to size just yet. This will cause a lot of issues especially in the clean-up process.
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Select Window > Preferences, then change the precision to as high as possible.
Note: You probably shouldn’t do this while actually working on your model making large changes, as this will slow down the software significantly.
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Group the model into manageable chunks. In order to group some elements, select them and then right click on them, selecting Make Group. If you make a mistake while grouping, you can ungroup by selecting the group and right clicking again, but selecting Explode instead.
Note: Grouping the model ensures that your computer doesn’t crash when it tries to clean up the entire model.
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Select one of these groups and go to Tools > Solid Inspector.
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There will likely be multiple items such as “Reversed Faces” and “Stray Edges” that will have a button next to them that says fix. Click these to deal with the relevant issues.
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There may be some other items that say “Info” rather than fix. These represent issues that Solid Inspector can’t fix because there are multiple possible solutions. Clicking info will highlight the relevant issues – you’ll need to fix these yourself.
Note: A common issue that will say info is when there is an open surface that isn’t planar. To fix this, draw lines that split the surface into planar parts.
- If you’ve managed to fix everything, you should see a window like this when you open Solid Inspector!
- After this, go to Window > CleanUp3 with one of the groups selected.
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Make sure that either the Local or Selection radio button is selected, Model will ignore your group and try to clean everything.
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If you have any hidden geometry that you would like to keep, either unhide it temporarily or uncheck the Erase Hidden checkbox.
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If you exported from Revit, it is highly likely that you will want to keep the Merge Adjacent Surfaces checkbox ticked, as walls and ceilings do not automatically ‘connect’.
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For the other buttons, leaving them as they were will most likely be fine. If you’d like to understand what any of them do, mousing over them will give you a description of how they should be used.
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Click on the “CleanUp” button to start the process.
Note: Repeating this method to clean your model regularly throughout
this process will reduce the amount of errors you have to deal with
later on.
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The maximum print size on the Ultimaker printers is 223mm wide by 223mm deep by 300mm high. If your model is larger than any of these dimensions, you’ll need to split it up.
Note: If it is only just larger than only one of these dimensions, you may be able to rotate it to fit it in. Here is the formula for working out whether your model will fit on the 3D printer:
Formula: (Width <= 223 AND Depth <= 223) OR (Width+Depth)/sqrt(2) < 223)
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When splitting the model, the technique used goes through everything in that slice when not inside a group, and only whatever is inside the group when in a group. For example, the following can’t be cut in the order blue > red > green, because blue will cut all the way through the buildings. Rather, it should be cut with red first.
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The following is trickier, as there are no full length cuts to base the other cuts off of. To deal with this, either red or green should be cut first, the other next, and then blue last off of the red cut. Whichever cut was made through the right piece can be patched together again using the CleanUp tool used earlier (Merge Adjacent Surfaces).
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Just before cutting, you need to duplicate the item you want to cut.
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In order to actually start cutting, select Tools > Section Plane
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Now select a surface that has the angle you want to section from.
Note: If you want to create a section on an odd angle that none of your surfaces have, you’ll have to create a surface at that angle to base it off. You can then hold shift after hovering on this angle with the section tool and move it to a better location while retaining the angle.
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Once the section has been placed in the right location, right click it and select “Cut at Section”. Patch the hole of the surface up that’s left by recreating one of the surrounding lines.
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Repeat steps 5-7 for the duplicate, except flipping the section by right clicking and selecting “Reverse”.
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It’s possible to make some cuts that only go through a part of the model by grouping it appropriately, such as the red cut pictured below.
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After all the cuts have been made, it’s a good idea to clean it again (refer to the cleaning method above).
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If any part of your model has any overhangs, it will needs to be sliced. 3D printers can generate support structures, however the finish of the underside after the support structures have been removed is not the best.
Note: the 3d printers can handle an overhang that is under 30 degrees without needing to build supports.
- To slice the overhangs, follow steps 4-8, using the bottom side of the overhang as the slicing surface (if it is 90 degrees. Otherwise, make a surface that is parallel to the ground at the correct spot and use that). As always, it’s best to clean after this (refer to the cleaning method above).
- To scale the models down, select everything you want to scale and press S. The model should be in a wireframe yellow box with green cubes around it.
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Click on one of the corner green cubes. Then, type the scale you have calculated you want to achieve, with 1 being the original size. The scale appears in the bottom right hand corner of the screen. Press enter to set the scale.
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After everything has been resized, it’s a good idea to clean it once more (refer to the cleaning method above).
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The model should be ready for exporting. Make sure each separate piece is on the ground (although this can be fixed later in the Cura software).
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Copy each piece into its own separate SketchUp files.
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Select File > Export > 3D Model
- Then after choosing your file name, set the “Export type:” to obj, and click “Export”.
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To start the printing process, open Cura.
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Select File > Open File, navigate to your file, and open it in Cura.
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From within Cura you can do the following things to your model after it’s been selected:
- After fixing your model, ensure that:
Print material is set to PLA
Infill is set to Light
Enable Support is unchecked
Note: If you are unsure about the other settings, setting them to
this is recommended:
