CloudCompare forum

I have an E57 file (8GB, 314 million points), which I want to open in Cloudcompare, subsample, save and then import to Archicad 28. The Pointcloud is in SWEREF coordinates, and has to be shifted so its origin is the same as the origin in the Archicad file and DWG

The origin in the ArchiCAD file is shifted to the SWEREF system like this (mm):
X: -150 993.377
Y: -6 401 215.07

When opening the file in Cloudcompare, the pop-up for Global Shift/Scale suggests the following shift:

X: -151 000.00
Y: -6 401 000.00

I.e, similar, but not quite like the shift I have in the DWG.

So I switch these numbers to my own shift mentioned before, check "Preserve Global shift on save", subsample the cloud and save it as a new E57.

The problem is, when I import it to ArchiCAD, it doesn't land in the correct position. It's pretty close to the local origin, so it's not in SWEREF coordinates (which would mean that it would be much longer from the project origin), but it's not either shifted according to the numbers I put in.

It seems to be shifted around 78000 mm in the X direction and 104 000 mm in the Y direction - pretty random numbers not related to either the sweref coordinates or the shift I put in.

Any idea what seems to be the problem here?

Thank you for a very good software, It's been helping me lot already and this is just the final step.

Well the shift in CC is purely temporary. This should not change the output coordinates if you keep the 'Preserve Global Shift on save' option checked. Therefore, whatever values you input won't change the result. You'll get the same coordinates in the output file as in the output one.

For instance, have you tried to keep the default Global Shift suggested by CC? I guess you would have the same result.

Not sure where the shift you observe comes from.

Hm, ok! But in that case, is there any way to get the exact shift I want in the output file? I thought this method was the way to do it (i.e change the coordinates in global shift pop-up, and then check "preserve global shift on save").

So if you want to save an specific 'offset' in the file, then it would be the way to (setting the right offset at loading time - with the caveat that you can only use 2 digits for the Global Shift).

But E57 files have a different way to encode/save the offset compared to most other formats. It's done via a quaternion and a translation (the scan 'pose'). And since this 'pose' is generally the scanner pose, CC will try to preserve it and restore it.

The only way to trick the system would be to manually change the Global Shift (with 'Edit > Edit Global Shift & Scale') and translate the local cloud by the opposite quantity (with Edit > Apply transformation').

However, I am still unsure to see how this works with Archicad, but I guess it comes down to how it manages this scan pose information?