Generate real world meshes in Houdini using the Google API.
You need a google account to be able to use this HDA. The process is easy:
- To begin click-on this link.
- Click Start free on the top left corner, you need to be logged in with a google account like gmail. If start free is not present it's probably because you already use google cloud, so instead link on Console on the top right (should be here if you are logged), then click on the combo box on the top left, and you could jump to the step 6.
- Fill your country, your organization description (I personally put Business idea / startup idea) and agree to terms of service and click Continue.
- Fill your personal information and your credit card (but you should not be charged if you don't overuse it, the free tier is relatively big and the Tile API is supposed to be free for a year, but check it yourself) and click Continue.
- Fill the survey.
- Click on the top-right on My First Project, and them click on Create a new project.
- Give-it a name (I personally called it Geospacial) and choose no organization a press Create.
- Click on the Hamburger Icon on the top right. choose API and Service then Library.
- Search for Map Tiles API and Enable it (It should give you a key at this Stage Keep it and do not share it with anyone).
- Search for Maps Elevation API and Enable it.
- That's it for the Google Cloud Account.
You need to add 2 additional python packages, pygltflib to load gltf files, DracoPy to uncompress mesh compression from google used by the 3D tiles.
- Launch Houdini.
- Go to the top menus Windows >> Shell.
- Type hython -m pip install pygltflib to install the pygltflib.
- Type hython -m pip install DracoPy to install DracoPy.
- Quit Houdini.
- The 2 packages are installed, your are good to go to the next step.
Note: Some user had to install PIP, in this case follow the instruction here.
I use this node from Labs, so you need to install the Labs Package.
- Launch the Houdini Laucher and install the Labs/Packages.
If you don't do that, most of the things you will see in the viewport won't be textured. It's optional but very recommended.
- Open the Display Option.
- Go to the Material tab.
- Increase the Single Object Material Limit to a big number like 5000.
- Restart Houdini.
Place the EarthMesh node in your scene.
- Cache path Path of the temp cache (recommended value $HIP/Cache)
Configure the node with the right parameter for your usage. I suggest you start with the parameters in the screenshot, or use the test scene EarthMesh_Test.hip at the root of the repo.
- Google API Key Copy your key here.
- Cache path Path of the temp cache (recommended value $HIP/Cache). Make sure this really exist folder exist on your drive.
- Latitude Latitude of the area you want to capture, i usually do a copy-paste from google map.
- Longitude Longitude of the area you want to capture, i usually do a copy-paste from google map.
- Min Error The highest definition you want to use for your mesh, smaller number means higher definition. 2 is presently the best definition, maybe one day google will enrich their server with more detailed meshes.
- Max Error The lowest definition you want to use for your mesh, smaller number means higher definition. 60000 is presently the worst definition.
- Min Dist If the bounding box is below this distance, the resolution will be set to the MinError resolution.
- Max Dist If the bounding box is farther from this distance the resolution will be set to the MaxError resolution. If the distance is in-between the chosen resolution will be an interpolation between MinError and MaxError
- Show Bounding Boxes It's mainly an option I used to debug, it builds a mesh with the bounding boxes instead of the actual mesh from google.
1 unit in Houdini, is 1 meter in real live, the X axis point to the North, the Z axis point to the East.
To optimize and also limit the number of requests to the google cloud, I use a cache in a folder specified in the digital asset. If a file in the cache is corrupted (it's never happened to me, but for example if Houdini crashes or is killed while generating the mesh) it might result in various issues like crashing Houdini, if you suspect the cache to be the source of your problems don't hesitate to delete all the files inside. There is nothing in the cache that can't be downloaded again from the cloud.
There are currently a few warnings related to the labs's QuickMaterials node just after loading the HDA. I'll do some follow-up with SideFX, and figure out what the solution is.
- Make the download phase interruptible, presently you only rely on the max_meshes parameter to avoid a very long wait or an infinite loop while experimenting with LOD parameters.
- Optimize the mesh construction, I already optimized this part a lot. I will try to optimize it more. I am open to suggestions.
- Probably a ton based on your feedback.
I am not a legal expert, but the meshes from google are copyrighted. Be careful when using them in a project.