Where to start for Measurements?

[Jan21021]

Hehey Xbim Team.

Id Like to implement Measurements. (lenght, area, volumes)

First Question: This has not been implemented, correct?
Second Question: Can you give me some thoughts, ideas how i should go on this task?

best regards
jan

[andyward]

Hi Jan

So firstly no we don't have a measure tool implemented in the Web UI project - a Measuring example is in the XbimWindowsUI project. However the fundamentals are there in this Web project. For instance you can pick two spots in 3D, get the xyz and then calculate the distance between them, and convert to real world units.

This ought to be something you can achieve as a plugin to the viewer, without changing the core code. In general the existing plugins are worth a look at for inspiration. There are a few considerations/tips:

1. You'll presumably want to annotate the interface while doing showing the measurement length/area/volume
   The best way would be to draw this in the WebGL scene (although you could maybe annotate on top). To draw in the WebGL scene this will need some GL experience but maybe take a look at the Grid plugin which shows how to draw lines into the scene:
2. For presenting the data/measures you could render this is the scene, or you could overlay it in the DOM - take a look at the Pins example for a an idea of how you can do that - e.g. converting from internal xyz to DOM coords with getHtmlCoordinatesOfVector.
3. For a better UX, you'll probably want to have some 'snap to edges' feature which will need a bit of thought as you'll need to be able to locate nearest vertexes to an 'xyz' pick. Maybe @martin1cerny can provide some pointers on the best approach to this as the data is packed into a GL Texture.

Let us know if you have further questions and keep us in the loop if you decide to investigate.

[Jan21021]

Hehey Andyward!
Thank you so much for your detailed response!
I succsessfully created my own Plugin. Very Cool that this can be done so easy.
I tried the easy way to create WebGL messurement lines. My knowlege was not good enough, so now im learing WebGL to be able to do that :)

About the snap function: i wasnt able to get the vertices in the java library, only in the .net lib. since im anyway converting my ifc in a .net web app i could send those to the frontend, after some transformaions... but if there is a easier way, id like to hear that :)

Best Regards!
Jan