Civil 3D topo surface from drone imagery?

[Anonymous]

I have done a fair bit of googling on this over the past month and a half to try to determine the best route to go. I currently have C3D 2019 and have a free trial subscription of AutoCAD’s recap software. From what I can tell it looks like recap will take aerial imagery from my DJI phantom 4 and use it to stitch pictures together and allow me to export several different file types. However my main question is whether or not any of those file types are directly compatible with Civil 3D in order to create a topographic survey of a site? I have a decent understanding of how recap allows you to set and use ground control points on a particular coordinate system (I can set GCP’s with my GPS Rover). But again I’m just looking for clarification on whether or not AutoCAD’s recap software will allow me to go straight from that program into civil 3D for a topographic survey to build a surface with? Any information on this is greatly appreciated in advance

[rl_jackson]

To clarify yes you can go from Recap/Recap Photo to C3D. The point cloud tools are on the planning and analysis work space and also somewhat hidden under the surface pull-down of the default C3D ribbon

[Anonymous]

Awesome thank you! Do you know if anybody has posted videos or tutorials on this? Or am I kinda on my own to figure it out? I know Autodesk provides a ton of tutorials for various things as well as FAQ write ups for Civil 3D topics. Wasn’t sure if there might be something similar for Recap before I spend the money on it. I’ve got the ability to topo stuff with a GPS Rover on a 4wheeler and i’m hoping to verify how accurate the recap file data might be in conjunction with a basic GPS topo i’d do via 4wheeler. Just wondering if the drone is a faster way to do it and would like to experiment with it

[Mike.M.Carlson · Accepted solution]

Hello,  These videos should help.  Enjoy!

Recap to C3D:

ReCAP to Infraworks

[rl_jackson]

As @Mike.M.Carlson has shown there are many sources, Autodesk University is one also.....

Its more in how you want to learn...

I learn here just as you do, I share what Ive learned too....

[wesley]

Very interesting.  Can you set targets on the ground at intervals for more precision?

[Anonymous]

Yes ground control points can be set to increase accuracy. Take view here for more info. I just want to make sure it’s fairly seamless going from Recap’s file types to creating a surface in Civil 3D

https://youtu.be/u2A89YLaVP0

[Joe-Bouza]

Awesome Mike

[rl_jackson]

Personally I'm not a big fan of the IW workflow, it gives you a surfaces that is a grid verses a TIN. I do a Recap (adjust intensity) import RCP and create a surface that further deletes data (simplify about 3 times). to get the data to a realistic level...... (Remember all contours are fake... Who said that?)

[rl_jackson]

Yes you can set ground targets that collect position (XYZ), then feed that data to Recap Photo, to stitch the Drone Images together.

[Anonymous]

So what you’re saying is that with Recap it’s hard to get it to create your typical TIN surface because there’s such a large amount of data versus what a conventional total station topo would collect with points at a much less frequent interval. And you’d prefer to use C3D’s simplify command to reduce all the excess/unnecessary definition to make the surface a little more manipulatible? I am curious by what you mean when you say “they’re not contours” as I’m completely new to all this... are you saying they’re not legitimate contours in reference to a certain benchmarked elevation until you add GCP’s?

[stewart_agnew_bamnuttall_co_uk]

Tried creating my own topic but it wouldn't work - could one of the admins move it?

Background: (United Kingdom - Scotland)

I work as a civil site/construction engineer. I'm very accustomed to importing/creating surfaces in AutoCAD Civil 3D for earthworks volumes calculations. More recently I’ve been experimenting with photogrammetry using a personal drone with the ultimate aim of analysing the difference in accuracy between a traditional topographic survey and a survey produced using images captured from a drone. I was assuming the easiest way to do this would be to import a surface created from the drone images into civ 3D and comparing resultant earthworks volumes with those calculated from a surface created from an existing topo survey of the same location.

Further info:

• I’m in the process of setting up a new construction site on Stornoway
• We have multiple (accurately coordinated X,Y & Z) existing ground topo surveys of the site that I have imported into Civ 3D and processed to generate earthworks volumes
• I have undertaken a drone flyover (using a DJI Mavic Air), capturing 167 detailed & relatively accurately co-ordinated images (according to the map location generated in Recap at least)
• I have imported the images into various software packages including Autodesk Recap & precision hawk processing and exported various file types (incl. point clouds, shape files & etc.)
• I have managed to create surfaces from the exported files but have been unable to properly coordinate them (in terms of X, Y & Z) assumedly as there’s some conversion error occurring between the native LL84 latitude longitude format the drone captures the images in and the coordinate system I have been trying to export to
• I have tried exporting to various coordinate systems with no luck
• I have been able to attach point clouds & etc. to my existing model of the site but as the coordination is way off, I've had to manually move them into position. They look right - but this doesn't let me prove the accuracy of the drone surface and would not work for future locations where I don't have an existing model.
• I am aware that I can import & tag GCPs and this is something I will do to improve the accuracy of the model once I can get past this initial "teething" phase.

Is anyone experienced with creating coordinated surfaces from drone images using Recap or a mix of Autodesk software? I have access to Recap Pro (+Photo), Civ 3D, Navisworks & Infraworks.

If necessary I can upload/send/link you to the original files I've mentioned including the topo surveys and drone images so you can run through it yourself and perhaps better assist.

Thanks for your time.

Stewart

[pmSM8AB]

How does one adjust the intensity of the point cloud in recap?