export image to architectural scale or 1:1

[demetrisk]

Hello all,

I am trying to export an image of a lidar scan to scale from cloud compare. I wonder what I am doing wrong as I end up with an odd scale on export. Here are my steps, If anyone can advise:

1. To export the image I use the rasterize tool with a step of 0.001, and that makes an automatic grid size. I select X axis for the projection to get a side view, and everything looks great in the preview.

2. I then import the rasterized image it into Autocad or Vectorworks, and I anticipate the scale of the png to be 1:1 or 1:10, but its about 3.5 times smaller than the 1:1 when I measure it. For example a staircase step measures 50mm instead of 175mm in height. Since this is an ortho view, I would expect it to somehow retain the scale.


Is this the wrong tool for what I am trying to achieve? Is there another way I can export accurate architectural scale orthoimages (or 1:1) from cc?


Best,
Demetris

[daniel]

Well, if you export as a PNG, you lose the geofencing. Still the scale of one pixel should be the one you've set in the Rasterize tool... Unless the cloud had some strange units initaly (CloudCompare doesn't manage units, it reads the coordinates as they are in the file).

Another option is to export the raster as a geotiff (to keep the georeferencing). However, I don't know if Autocad can load this format.

[demetrisk]

Hi Daniel,

Thanks so much for the reply. I've discovered a plugin for Autocad that imports the georeferencing from the image on load.
If anyone else is trying to solve this, I found the plugin is from Nubigon.

Also, Bricscad automatically has image georeferencing import available.

Best,
D

[libak]

I have the same problem. When I use rasterize tool:

> select point cloud
> Hit rasterize button
> set parameters
> update grid
> Rasterize viewport shows my point cloud, ok.
> Export > Raster
> Export RGB colors > OK
> Save as type: geotiff (*.tif)
> Save
> In AutoCAD I enter IMAGEATTACH, and set scale to 1
Now the length of the image in ACAD is 1mm

I don’t think this is very useful, I would like the image to be same scale as the point cloud was in CloudCompare.

A workaround is to scale image I ACAD to the X value in Box dimensions in CloudCompare.

Note: when I export geotif/ orthophoto from Cyclone/ Faro the scale is correct when importing orthophoto in ACAD.

Any help on this would be greatly appreciated

Thanks

[daniel]

Can you maybe share the output raster tiff image with me? (admin@cloudcompare.org)

And maybe a screen capture of the Rasterize dialog.