Archive | April 9, 2013

Setting up your Revit project to model point cloud data

The best format to bring your point cloud directly into Revit will be in *.pcg format – If you are yet to index your files, you may have any of the following files types: *.fls *.fws *.las *.ptg *.pts *.pcx *.xyb *.xyz – If your files are still in one of these raw formats, you will first need to index your files. You can do this directly in Revit, or if you’d prefer, check my old post here to find out how to do it outside of Revit.

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If you are working with point clouds, you are probably aware that setting up the points to be re-modeled properly within Revit is essential. When you import your point cloud by shared coordinates, you are left with a 3D model of your points. Although this may look good, it’s not going to be enough information for you to model the building. What we need to do is set up sections, levels and elevations in order to give us a good chance of capturing all the details.

ImageAs you can see from the image above, when you import a point cloud into Revit, you do not get a very clean view of the model compared to when you view it in a program made for this specific purpose, e.g. point tools.

The first thing that we will do is create a section view on Level 0. Right click and zoom to fit > Draw a section from the left to the right hand side of your screen to ensure you will be intersecting your point cloud. Once you have done this, go to your section. If your point clouds shared coordinates file was set up correctly, you will now see your model in the section view. Unlike 3D views, section views allow you to add levels and elevation tags to your model.

ImageSet up your levels as required. There should hopefully be enough detail at this point to be able to identify where your floor slabs are starting and where your ceilings are located. Simply create your levels and as normal, you will notice new floor and ceiling plan views appear in your project browser. Once you have you levels set up, it will most likely be necessary to adjust the view range, in order to cut out any noise, or objects in the point cloud that you don’t want modeled in your Revit file – for instance bins, storage etc. I personally like to use 2 plan views for each level – 1 with a low view range and the other with a high view range. This will make it clear which elements are located where in the building. Using sections in certain areas will most likely be compulsory.

ImageNow you have 2 views of each level it will be easy for you to begin modeling the walls, openings etc inside of Revit. As you can see from the image below, just changing the view range makes a huge difference to the same level and is a very important aspect of modeling from a point cloud. If you neglect this, you may well miss vital parts of the building that need to be modeled.

ImageOnce you have started modeling your walls etc you will probably come across certain objects for example beams and columns which need to be modeled. Although, of course Revit has standard beams and columns in the generic libraries, I find it better to model these as structural in place components – This way you can recreate a very close replica of the objects in question.

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If you have surveyed the building with a scanner such as a Leica model, you will most likely have TruView files to go along with your .pcg or raw format files – These will come in very useful when you are unsure about how certain objects are joining together etc. Be sure to make use of these files which can be opened in Internet Explorer with a plugin enabled. They are 360* panoramic photos of the areas which have been scanned. (The scanner also photographs the building as the points are being scanned.)

ImageAfter a bit of time and a lot of patience you will eventually see your existing building come to life in Revit. If you are having any troubles with modeling point clouds, feel free to get in contact and ask any questions you may have. I will be posting a blog shortly about jumping geometry (see below) due to positioning of point clouds in relation to shared coordinates – and a solution to fix this problem!

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