Revit model import & sample to .las

[Acosgrv]

Afternoon

Beginner with this sort of thing, so apologies if I'm missing something obvious, but I hope someone can offer a bit of guidance.

I'm trying to create a sampled .las cloud from a Revit model. The important things are that the geolocation is maintained, and the points are coloured, not with perfect textures or anything but just different colours to give the same effect as displayed in Revit.

Although I've cracked the first bit it doesn't seem like a particularly elegant solution. The standard OBJ export in Revit doen't seem to give the correct geolocation, so all I've managed to do is commit the ifc file to a dtm surface and export that as an OBJ. It gives me an OBJ in the right location, but loses the colours. (Any help with Revit to geolocated OBJ will be much appreciated)

When I import the OBJ to CC it is only visible with 'Materials/textures' UNselected (its invisible when selected) ? Is there some way of applying an .mtl file to colour the cloud once its sampled?

Thanks for any help in advance

[daniel]

Could you export one standard and not-georeferenced OBJ file (with a nice texture?) and the other way as you described, and align the first one with the second one to restore the good coordinates?

And if you don't see the entity when the material is enabled, it's could be because something is wrong with the .mtl file. Typically that the 'Tr' parameter is mistakenly set to 1.0 (= full transparency) instead of 0.0 (= no transparency).

[Acosgrv]

Hi Daniel, thanks for getting back to me

Since I asked I've managed to figure out some of it, the colouring is all sorted thanks to another answer I found (which I can't find now, but I think you provided) regarding edit>mesh>convert texture/material to RGB.

And I've been working on exactly what you've suggested, the OBJ won't export in real coords, so I've been trying to figure out how to apply the translation/rotation required. I have the Eastings and northings from Revit, and I've applied the 'global shift', which gets me close (see attached, I'm overlaying a sampled revit model on a georeferenced survey, the cyan line is an indication of where it should be) but there still seems to be an issue with 'project north' Vs 'True North', i.e. it seems to be out by the 46 ish degree difference. I've then tried the translate/rotate tool which has moved it, but not to the right place. I'm not sure if the point around which I'm rotating (in z axis) is the point I think it is, i.e the revit base/survey point

It's simple enough to find coords on the model in the location I want it, say three corner points of the roof for example. Can you point me towards an easy way of 'applying' those coords to my non located file? (I feel like this is basic stuff in CC but, again.. beginner, any help will be massively welcome)

Thanks again

[daniel]

Do you mean this tool? https://www.cloudcompare.org/doc/wiki/index.php/Align