City of Madrid

Project Details

The entire display will end up approximately 800mm x 1000mm (31.5" x 39.4"). Feel free to scale down if you want. This is a very involved project. It will take a lot of time and effort, but it looks amazing and gets LOTS of compliments.

If you're wanting to learn how to create this with any LiDAR data of terrain or city, scroll down to the bottom for a tutorial.

Materials

• 20 x 3D printed tiles (199mm x 199mm tiles)

  • Each tile will use 200-350g (so approximately 7kg of filament)

  • I used Overture white PLA

  • Blender exported them in meters, so your slicer should adjust to mm automatically. If not, scale by 1000.

• 4 x "Trim - Height"

  • If your printer can't fit it, you can scale the long side by 50% and you'll just need more "Trim Support" parts.

  • Instead of printing these I laser cut them out of 1/16" wood

• 3 x "Trim - Width"

  • If your printer can't fit it, you can scale the long side by 50% and you'll just need more "Trim Support" parts.

  • Instead of printing these I laser cut them out of 1/16" wood

• 10 x "Trim Support"

  • Provides more rigidity to the trim. Some of the sides of the tiles are thin.

  • You will need more if you make the trim pieces smaller.

• 4 x "Trim Support - Corner"

  • Provides corner support for the trim, and improves the aesthetic.

• 1-2 - 1/8" Chipboards to cover back the tiles

  • Provides the structure needed to hang on the wall

  • You can use thicker boards, you will just need to scale the trim support height to allow the thicker board.

• Picture hanging set

  • The type with steel cable and screw mounting points.

• CA glue

  • aka superglue. I like the Starbond thick CA glue. It's not very runny and works well on just about everything I've used it on.

• Optional - Wall mounted artwork light

  • I used this one from Amazon. It's rechargeable and has a timer to turn off after a set time to preserve battery. It's good if you're not allowed to do any electrical work.

Printing

Print times will be anywhere between 1 day and 2.5 days.

I recommend writing the filename and arrow direction pointing north on the back of the tile so you know how they line up. You will probably have to refer to my photos to figure out which way is north.

For example: 1W-1N ^ 

Print Settings

Print Issues I Experienced:

I recommend using the test tile provided to test out these settings and make your own decisions based on what works best for your printer and needs. Do a few iterations to dial in good print quality and quicker print times. These are long prints, so make sure you know these settings will work well.

Be patient:

• These are very large files. In hindsight I could have reduced the detail more.

• You may have trouble opening them in your slicer and getting them sliced if you don't have a good computer.

• Slicing will take a long time, even on a gaming PC.

• These are also very long prints.

Assembling

1. Line all the tiles together (refer to my photos to figure out how they line up, unless you like puzzles)

   1. Determine if any tiles have gaps due to lack of flatness and sand them until the tiles sit flush with minimal gap

2. Place them on your boards, mark lines for where to cut, and cut the boards to size

   1. Having two boards is fine, so long as tiles overlap and you don't join them close to where tiles meet.

3. One by one, apply a liberal amount of CA glue on the back of the tile and press for 30-60s on the board

   1. Start with one corner tile and move across and down

4. Apply glue to the sides of the outer tiles and attach the trim pieces

   1. The trim supports will hide any gaps you have in the trim

5. Apply glue to the trim supports and attach to the trim and back of the board.

6. Screw in wall hanging hardware

   1. Do NOT use screws longer than .5" or you'll risk punching through the other side!

   2. Space about 15 inches apart near the top 2/3rds of the board.

7. If wanted, add a wall mounted light above it (it looks best with a light at the side).

Why Madrid?

I lived in Spain for 2 years and in Madrid for 6 months. I look back to that time with fondness so I wanted to make this display once I learned how to make the files. Now onto the tutorial!

Tutorial to make any 3D printable file from LiDAR data

Prerequisites

• Software needed (all free)

  • CloudCompare (CC) - For processing LiDAR point cloud data into a volumeless STL

  • Blender - For giving the STL volume and a base to print

  • Your choice of slicer - I recommend Prusaslicer (we're on Printables, so I'm assuming we're all using this anyways)

• Hardware

  • A half-decent CPU (i5 or Ryzen 5 or better)

    • I had a Ryzen 5 2600 when I made these in 2022, it's 3.9Ghz 6 cores.

    • Most important with slicing the model.

  • 16GB RAM minimum, more recommended.

    • Your RAM does the heaviest lifting here.

    • I have 32GB 3000Mhz DDR4 and at times blender used almost all available RAM.

    • Your RAM will dictate the size of model your PC can handle. Go too big and your computer will really struggle and might even freeze.

  • A dedicated graphics card will probably be useful for viewing things smoothly.

    • I'm not sure how much this matters, but it does put load on my GPU when viewing the point clouds on CC and the mesh on Blender.

Guide

Obtaining LiDAR Point Clouds

Finding the right data can be tricky, and it depends on what kind of print you're wanting. If you only want terrain, then it's easy. If you want buildings and cities, you will have a harder time. I've noticed a lot of LiDAR files have filtered out buildings and only include terrain. You'll need to do your own research to find your data.

In the case of Spain, they have pretty much their entire country worth of LiDAR data available free of charge provided by the Spanish government on this site.

You file needs to be a point cloud file. These will be .LAS/.LAZ files for LiDAR.

Modifying LiDAR Point Clouds and Creating STL Mesh - Cloud Compare

1. Open the .LAZ/.LAS file in CC. - You can open multiple at once, and they will be placed together according to the geographic coordinates in the file.

   1. Click apply

2. Merge the point clouds you want to print as one tile

   1. CTRL click all - Edit > Merge

3. Reduce the amount of points

   1. This is very important. These files have anywhere between 5-15 million points. When you click on the model you can see the amount of points in the properties box. When the mesh is made it will be creating triangle surfaces between every point. When you go to blender you will have a LOT of surfaces it needs to process and can be too much for your computer and you will run out of RAM fast.

   2. My suggestion is that for every 3D printed tile (around the 150-200mm size) you only have 1.5-3 million points.

   3. Edit > Subsample > Random, slide until you get to the amount of points you want.

   4. If your PC struggle's later on and runs out of RAM in Blender, reduce the amount of points further.

      

4. Clean up data if needed

   1. Rotate to look at the data at the side, are there any random points? These will cause spikes in your mesh and need to be removed. In Tools > Clean > SOR Filter, you can remove outliers.

5. Create a mesh from the point cloud

   1. Edit > Mesh > Delaunay 2.5D (XY Plane)

   2. Keep max length of triangle set to 0.

6. Inspect mesh for any random spiks (clean if necessary)

7. Save as STL

   1. File > Save - Make sure STL mesh is selected

   2. Select Binary

Creating a Solid STL from Mesh - Blender

1. Import your STL mesh from CC

   1. File > Import > STL

2. Resize the mesh and cube

   1. It will probably be massive when it imports, mine imports at 1km x 1km

   2. Click on the < arrow to open the transform box

      

   3. Change the dimensions to the size you want to print, then look at the scale equivalent and put that scale in the Z scale box (this will scale your height accordingly.

   4. Now click on your cube and change the X and Y dimensions to be slightly smaller than your STL mesh.

3. Center your mesh if needed

   1. Sometimes it will import offset in the X and Y for some reason and will need to be centered where the cube is

4. Move your cube in the Z direction to the proper thickness you want for your print

   1. Keep in mind due to elevation change, some tiles will be lower than others. If you go too thin, some other tiles will drop lower than your thickness allows.

   2. Remember the scaling and position values! Especially the Z position value for the cube, each tile will need to be the same to keep the same level.

      

5. Cut the cube with the mesh

   1. Click on the cube then click on the blue wrench (Modifiers tab) on the right.

   2. Add modifier > Generate > Boolean > Intersect > Object: Name of mesh

   3. You will now find out if your model was too big. I recommend opening Task Manager and monitoring your RAM usage. You'll see it go up significantly. It may take a while for blender to do the operation so be patient.

   4. When done it will show a preview. Click on the down arrow and then apply. Your cube is now the STL you can 3D print.

      

6. Export as STL

   1. Hide the CC mesh

   2. File > Export > STL

      

7. Now you can import into your slicer and print!

LiDAR Attribution statement:

Derived from LiDAR-PNOA-cob3 2022-2025 CC-BY 4.0 scne.es