Introduction: 3D Design and Printing Using Free Software

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About: When I'm not waking up at 5:30 in the morning to feed my cat. I am designing homes and professional offices for my clients. I enjoy pushing the boundaries of 3D software and VR applications.

There are many resources for ready-to-print 3D files, but what if you want to design and print your own creation? (Which is where all of the fun really is) This Instructable opens the door to the creative power that lies within you and best of all I will show you how using nothing but free software.

Step 1: Let the Downloading Begin

You will need a few software packages first:

  • SketchUp Make sketchup.com follow the on-screen steps and choose your operating system.
  • netFabb basic netfabb.com choose your operating system on the download page

I have successfully tested the creation of .STL format files with this combination of software on both PC and Mac platforms. .STL files are the common file language used by many of the 3D Printers available.

Step 2: Getting SketchUp Ready

This step is all about getting the STL plug-in installed. Once you have SketchUp installed you can start designing, but you won't be able to create the .STL files that you will need later on until you add a .STL plug-in to the software.

To add the STL plug-in, open your copy of SketchUp. Once SketchUp is open look for the "Extension Warehouse" icon on the tool bar and click on it to open the Warehouse. This will take you to a web based area with many SketchUp compatible plug-ins. In the search bar within the warehouse type "SketchUp STL" or look for SketchUp STL in the "Top Extensions" section on the right of the screen. Click on the name of the STL extension and you will be taken to a download page. (Sorry no direct link available, you need to go through the warehouse to get this) Once on the download page you will need to sign in or create a free account to download this plug-in. After downloading the STL plug-in package, open it and follow the prompts to install it within your copy of SketchUp.

After installation of the plug-in, reopen SketchUp to see if the plug-in is present. You will know everything is in order by going to the "file" tab and seeing "Export STL" as an option.

Step 3: Now the Fun Begins

Now you are ready to create or edit your own 3D design within SketchUp. I feel it is a fairly intuitive software to use and there are many tutorials available. If you are new to using this type of program here is a good resource to get you started

Step 4: Converting Your SketchUp File to STL

This step is a simple one, but there are a few things to know. When you are finished with your creation in SketchUp simply click on the file tab, click on the "Export STL..."

This will bring up a dialog box with a few export options.

  • First there is a check box that reads "Export Selected Geometry Only". If there is check in the box, it will only create an STL out of anything that is highlighted (selected) in your model. This is a handy feature if you have a lot of reference drawings within your model. If you intend to convert everything contained within your model leave this box unchecked.
  • Second, you will need to select the unit type that you are exporting. If you created your model using full unit sizes within SketchUp simply select the top choice "Model Units" the other choices are imperial or metric units.
  • The last option to adjust is "File Format" the two choices are "ASCII" or "Binary" ASCII should work fine for smaller projects. Binary creates a more compressed data file for the printer. Most machines take either file type, but you may come across one that requires one type and not the other. My advice is to stick with ASCII for now.

Now you're ready to hit the "Export" button. Here you will be prompted to give your file a name and specify the location that it gets saved to.

Step 5: Checking for Leaks

One of the downsides to SketchUp is that it is not a solid modeler program. In other words, a cube created in SketchUp is hollow inside, just as if you taped six equal squares of paper together to create it. So once the STL file is created we must use another program to check it for "Leaks".

By this, I mean that you must check to make sure the meshes that create your model are all filled in. You see, the surface of your model is created by a mesh that is comprised of many little triangular faces. Sometimes the faces do not get filled in and create the "Leaks" that I am talking about. When this occurs you will get errors in your print job. I have found that netfabb Basic is a good program for checking for those leaks and repairing them.

So with that said, now is the time to open your saved STL file in your copy of netfabb Basic. Once your model loads in do not be surprised if you see the warning triangle with exclamation point to the lower right of your model on the screen. This means that errors "Leaks" have been found.

Step 6: Repairing Your Meshes

Within netFabb basic look for a red cross 'first aid' icon labeled "Repair" This command will also be located under the "Extras" tab. Click on repair to have netFabb basic automatically do the repairs for you. Once the repairs are complete you can analyze your model again.

Located under the "Repair" icon in the "Extras" tab is an icon labeled "New Analysis" Click on this to review your newly repaired model. On the right of your screen there will appear an analysis report that indicates, among other things, number of holes and weather your surface is closed.

If all was repaired on the first round, "Holes" should read 0 and "Surface is closed" should read "Yes"

If you still have holes or the surface is not closed then repeat the "Repair" and "New Analysis" steps until you get a model with no holes and a closed surface.

Generally, the more complex the model the more times you may have to run the the repair steps. If however you need to do this more than 5 times you may need to review your model for larger issues.

Step 7: Exporting Your Final Version

Now that the repairs are completed, save your model in the netFabb format. With the model saved you can now export it back into STL. To complete the export go to the "Part" tab and look for the "Export part" button.

"Export part" will bring up a host of export options. Choose either STL or STL (ASCII). (Most 3D print machines should take either format but you may need to consult your owner's manual to be sure.)

Give your part a unique name to differentiate from your original version of the file. I use (file name) _final.STL

Congratulations your part is ready to 3D print!

Step 8: A Recap of the Workflow

For those who want the steps without the explanations here they are again:

  1. Download SketchUp Make
  2. Download netFabb Basic
  3. Download and install the STL plug-in into SketchUp Make from within SketchUp Make
  4. Draw your 3D part using SketchUp Make
  5. Export your 3D part into the STL file format
  6. Open your 3D part in the STL format within netFabb Basic
  7. Repair your part within netFabb Basic
  8. Analyze your part within netFabb Basic
  9. Repeat 7 and 8 until your 3D part shows no holes and is a closed surface
  10. Save your repaired part in the netFabb format
  11. Export your newly saved 3D part as a new STL (using netFabb)
  12. Now your ready to 3D print!
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