Messages

16

General / Re: Point clouds in Autocad 2016

« on: November 02, 2015, 07:33:02 PM »

OK, I've found it.
BUT.... i tried on several models, and the progress bar of the export to .RCS always stops after 9%, but no file is written....

17

General / Re: Point clouds in Autocad 2016

« on: November 02, 2015, 04:28:46 PM »

Hello Dieter
Thank you for your help.

I tried the workflow you suggested (Agisoft version)
I exported the data from Photosca, as .TXT file and imported it in Recap. Everything OK
I cant't find an option to define "raster to the minimum" and the only option I have for saving the file is .RCP. No "single .RCS" available

When I attach the resulting file to Acad, same results than previously: I can snap on individual points in the cloud, but not on planes supposedly recognised by Recap. As a consequence, dynamic UCS doesn't work as well

18

General / Re: facade of building more clear

« on: November 02, 2015, 11:56:03 AM »

check the image quality.
You will never get a good  result if the photos are not good enoug.

Check for image sharpness and global contrast.
A rolling shutter camera such as the one of the DJI Phantom 2 is clearly not the ideal solution for photogrammetric processing (the shutter generates non-parametric geometric distortions and photoscan can't handle these). Better to use a camera with a "photographic" shutter. If not possible check if the stabilisation gimbal works well (having less vibration will reduce the effects of rolling shutter).
Probably having more photo will help, by "diluting" the errors made on individual pictures, but this is more an "educated guess" than a scientific fact....;o)

19

General / Re: Point clouds in Autocad 2016

« on: November 02, 2015, 11:46:55 AM »

I have used ReCap, and the only way to align the coordinate system by using the "Ultimate" version and use the following method:

I think the method you describe here is to define the global reference system of the project ("WCS"). I'm looking for a solution to locally modify the local coordinate system ("UCS") to properly align current drawings. For instance define a UCS on a wall before to draw all windows on that wall, then another UCS on a roof plane, etc...
I do the global referecing within   Photoscan,  and as far as I can see, the imported cloud is perfectly referenced

20

General / Re: Point clouds in Autocad 2016

« on: November 02, 2015, 11:38:38 AM »

@nadar


I think it is a software Problem, because it dont work for me with laserscan data too in Acad 2016. The only thing what is working is the catching of a point in a pointcloud.

I will ask tomorrow my AutoCAD-hotline.

I was alos thinking about a software problem. I've read in a forum that it worked in 2015 version but no more in 2016.
I've tried the old version, but also with no success.

For me too, snapping to a point in the cloud works fine, but when I see the deme, having dynamic UCS would be really more efficient...
For the moment, I draw a planar triangle by snapping on 3 points on a wall, and use this polygon as a reference to create a local UCS. Not as straightforward as it could be....

21

General / Point clouds in Autocad 2016

« on: November 01, 2015, 01:34:54 PM »

I'm always looking for an efficient solution to draw and measure architectural features (windows, doors, etc.) from point clouds of buildings, obtained either with an UAV or with a pole.
I tried automatic feature recognition (e.g. PointFuse), but as the cloud is noisy, the extracted features are not accurate enough and/or splitted in too many faces.
I thing manual extraction will better suit my needs: I want to draw the architectural features directly on the cloud to obtain topologically "clean" polygons such as rectangles, volumes, etc.

The latest version of Autocad 2016 and Civil3D 2016 have very intersting functionalties to manage point clouds in such a way:

https://www.youtube.com/watch?v=rCR95F0Fo88

The general workflow is to prepare the original cloud (I'm usually working with .LAS files) in an external application, Recap. It will organise different files to merge these in a .RCP file that can be attached to an Autocad drawing. According to the demo, during this preparation phase, the software will "structure" the cloud, i.e. recognise planes in the structure of the cloud. Recap has a very simple interface, and the parameters for this segmentation does'nt  seem to be accessible to the user.

When the cloud is attached to an Autocad (or Civil3D) drawing, I can acess most functionalities such as slicing, automatic recpgnition of features in slices, etc. Snapping on cloud points works well.
Unfortunately, the possibility to modify the local coordinate system ("Dynamic UCS") by snapping on planes identified in the "structured" cloud doesn't work with me. Apparently, no structure was detected during Recap preparation.
I tried with many different Photoscan-generated clouds, and even with "pure" Lidar samples, but the result is always the same.
This functionality of Dynamic UCS would be very useful.
Does anybody already tried this ?  Is it a problem with the nature of the data generated by Photoscan ? I'm using .LAS. Will another format be more adequate ? Do I have to clean or reorganise the data in another software ?
Is the problem related to some settings in Autocad ?
Any suggestion will be more than welcome, because I'm sure this possibility to combine large point clouds with a 3D Cad software used widely by architects will be a great asset.


According to the demo, the

22

General / Re: Vertical error in DSM to Ground Control

« on: October 22, 2015, 10:39:45 AM »

Vertical reference in WGS84 system is sometimes based on an ellipsoid, and sometimes inegrates a local correction to better fit the geoid. In some regions, the difference can reach 50 m

23

General / Re: Measurement of deflection

« on: October 10, 2015, 07:57:43 PM »

have a look to cloudcompare

24

General / Re: What lens for my Nikon D50

« on: October 10, 2015, 07:56:37 PM »

prefer prime lens, not zoom

25

General / Re: Archicad

« on: October 10, 2015, 12:14:41 PM »

Not easy....
The best solution I found (so far ?) is to export dense cloud as .LAS, import in Autodesk Recap and save as .RCP then import it in Autocad.

All my attemps to get automatic shape recognitions are failure. Best results so far are with PointFuse, but you still neeed LOADS of editing to get valuable resulst.

The main poroblem with pointclouds is snapping on a fuzzy surface....

Good luck and keep us posted about your results

26

General / Re: Potree - point cloud export

« on: October 05, 2015, 06:55:51 PM »

this sounds like chinese to me.
Is there a SIMPLE way to intall a WIN64 executable and run as a viewer ?

27

Agisoft Viewer / Free viewer with measuring function ?

« on: October 03, 2015, 11:36:12 AM »

Is there a simple free viewer capableto display large points clouds and/or textured meshes and allowing to read coordinates (real world) and to measure distances and surfaces?
Could work on local data or on data stored on a cloud

28

Feature Requests / Re: Request: Dense Cloud Filtering

« on: October 03, 2015, 11:29:05 AM »

New function of mesh smooting is fine, but has a terrible impact on buildings (rounded corners). Is there a possibility to have a filter preserving planar surfaces ?

29

General / Re: Photo centres

« on: October 02, 2015, 07:34:31 PM »

You can export camera positions (X,Y,Z + attitude angles)

30

General / Re: Depth difference of dense point cloud models

« on: September 25, 2015, 05:54:22 PM »

try this

http://www.danielgm.net/cc/tutorials.html