How to edit STL and OBJ files with Tinkercad

 I was recently asked if it is possible to edit STL files in TinkerCAD. The answer is yes. It's a bit of a fiddle but once you've done it once, it gets a lot easier.

You can remove unwanted parts of an STL file, edit parts of a file independently of the other parts, paste parts of one file into another, move parts of a file around independently of the other parts.

By using the following steps - any of the above is achievable

STEP 1 - Create a New Design in TinkerCAD

Go to the Tinkercad website and if you don't already have one, create an account.

Once you have done so you will be taken to the Tinkercad Dashboard where you need to Create a new 3D Design

STEP 2 - Import the .STL or .OBJ file you want to edit

Click on the Import button in the top right corner of the window.

Browse to where you have saved your STL or OBJ file and Open it.

Your file will now appear on Tinkercad's Workplane.

STEP 3 - Rename your file

Click inside the name box in the top left corner of the screen. Tinkercad creates a nonsensical name for your new file. You can work with that name or give it a more recognisable name. 

STEP 4 - Save your new design

To save you new design, click on the Tinkercad logo in the top left corner of the window

This takes you back to the dashboard, where your new design should now be shown. Click on the Tinker This button above your new design to go back to the Workplane

STEP 5 - Decide what needs to be separated 

Decide which part of the file you want to remove, move or rework. 

Now drag a Box Hole shape over the part you want removed. Resize it by moving the handles at the corner of the shape until it covers the part of the design you want to remove. 

NOTE: If you have a complex shape overlapping with other shapes, you may need to repeat this step and Steps 6, 7 and 8 until all the parts are removed.

STEP 6 - Highlight the box and the shape

Drag over the Box Hole and the shape to highlight both of them (NOTE: You are shown how many shapes have been selected in the box on the right of the screen - ie Shapes(2) - you will need need to ensure two shapes to have been selected).

An alternative way of highlighting or selecting is to click on one shape, hold down the SHIFT key and then click on another shape.

STEP 7 Group the hole with the design

Click on the Group button in the top right corner of the window.

As you are combining a 'hole' with a shape, anything covered by the 'hole' will now be removed.

STEP 8 - Rename the shape

The new shape now needs to be renamed so we don't accidentally overwrite the original design. As before, click in the Name pane in the top left corner and rename it.

STEP 9 - Go back to the original design

This can either be done by going back to the Tinkercad Dashboard (by clicking the Tinkercad logo) or more quickly by clicking on the Recent Designs button next to it.

If you click the Recent Designs button, you will be shown a list of your recent designs with the most recent at the top of the list. Click on the Tinker This button to open your original design,

Step 10 - Remove the other part of the shape

This time we will remove the other part of the drawing in the STL (or OBJ) file. As previously, drag a Box Hole shape over the other part of the shape and resize it so it covers just the other part of the design.

As previously, now highlight/select both the Box Hole shape and your original STL design and then click on the Group button

Step 11 - Copy the remaining part of the STL design

The other part of the design will now have been removed. We now need to copy what is left. Click on it to hightlight/Select it (notice how the outline of just that part of the shape is now shown) and then click the Copy button in the extreme left corner of the window (alternatively, you can copy the selected part by holding down the CTRL key on your keyboard and pressing the C key)

STEP 12 - Open the second file you saved

We will now open the second file - but clicking Recent Designs and then clicking Tinker This to open the relevant file.

STEP 13 - Paste the part of the design you copied back into this design

This may seem like a strange thing to do, but we are now going to paste the part which we've just copied back into this part of the design, by clicking the Paste button (or holding down CTRL and V)

This will paste the other part of the design back on to the WorkSpace. However, this time it is a completely separate part which can be moved or resized without affecting the rest of the design.

STEP 14 - Move or reshape the part.

In this case, I wanted to move the parts closer together to take up less space on the printbed.

STEP 15 - Export the new shape

The modified shape now needs to be exported as a new file (or if you give it the same name as the original it will replace it).

Click on the Export button (top right)

We want to export the whole thing so make sure the Everything in the design radio button is highlighted (as shown). If you only want to export part of the drawing, Highlight or Select it and then click the Export button.

Navigate to where you want the file to be saved and then you can go back to the Tinkercad dashboard (by clicking the logo) to make sure your new file has been saved.

Summary

That's all there is to it - in essence what we have done is

1. Imported the file we want to edit
2. Saved it as a Tinkercad file
3. Removed various parts and saved what's left as separate Tinkercad files
4. Opened one of the saved file and copied the part
5. Pasted the part into another one of the saved files so the parts can be edited, resized or moved separately
6. Exported the newly edited file

If there is anything else you are struggling to get Tinkercad to do, leave a comment and I will do my best to address it.