Distorted 3D map


#1

Hi Everyone,

Today I had a go using the 3D Mode. I am trialling this function because I have a client who wants me to map his property where there are some large Pine Trees which he is concerned about falling on his house. I will map his property but also thought about a 3D map so he can get a perspective of the height of the trees and how far away they are from the house.
I have shared this 3D model which was just a trial today before doing the real job this week.
Unfortunately I had do fly early evening and I am wondering if the cause of the distortion on my model is due to the sun being lower and causing shadows.
I would really love some feedback and tips to producing a great model, I have read about flying separately and taking still shots at a lower alt with camera at 45 degrees to the structure, is this a must to get the best model.
Lastly, is there a way to get true measurements off the model, I use annotations for widths etc, but need vertical heights for the trees vs the house so was wondering if there is a way to do this within DD

Many Thanks
Chris

http://www.dronedeploy.com/app2/data/5aaa02ca7e8d4f7fac4efca1;jwt_token=eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJ0eXBlIjoiUmVhZE9ubHlQbGFuIiwiaWQiOiI1YWFhMDJjYTdlOGQ0ZjdmYWM0ZWZjYTEiLCJleHAiOjI1MzQwMjMwMDc5OX0.K0_58OBdJBzq6bboScUVexi3XixcwPN4G56EjgVvrb8HM2HnjvIVsG7zoi8RFUNIRDi0TDLT4H_d_KFwRhVByg


#2

Sculpting good 3D models with a drone is part art and part science at this time. Gaining experience in how best to apply the techniques to optimize the models is the best approach.
Along with the Nadir grid photos, getting good sequential overlapping oblique images without the sky in them is key. Many people use the POI feature in the DJI Go app to get good overlapping oblique images or just fly manually.

These documents give good insight on how to go about it.



#3

As an arborist I have been trialing 2D and 3D mapping of trees for the past year. Trees are very difficult to get a good 3D map. The branches are too small to register well in the obliques, although the verticals do fairly well from that perspective. Experiment, but don’t expect too much from 3D.

I highly urge your client to seek advice from a good local arborist as to the condition of the trees. Trunk and root problems can be hidden, and certainly not visible from the air. Search on International Society of Arboriculture and American Society of Consulting Arborists to find competent arborists.


#4

I would say that the 3D map looks fair, it doesn’t get much better with the automated flightpath imo.
Remember to make sure the height is not too high (or low so you hit something), making sure also that the distance to the object is ok, it should not be to narrow around the building, as that will definetely distort, make a circle around the building, take some ‘angled shots’ to get the facades better. Then pool all the images into the 3D map, that would improve it a bit I think. The calculation uses the GPS and angle position when doing the 3D map as well. One thing that will trick it up is roof overhang, ie. the small part in top of the wall, below the roof.
I did a demo of a residentail area, and that was with 123 images, though no angled shots at the time:
http://www.dronedeploy.com/app2/data/591dd3419ef4e0673abee3f2;jwt_token=eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJ0eXBlIjoiUmVhZE9ubHlQbGFuIiwiaWQiOiI1OTFkZDM0MTllZjRlMDY3M2FiZWUzZjIiLCJleHAiOjI1MzQwMjMwMDc5OX0.0hCl3e1V2TojsdJ9O-klOfvMbTbQjZT62V9YDqPLqaq8uKZaCr3M1KypiyRRDBn4HiHqjeDsR-gcyRmJ-Y2zUg
And you can see some of the facades have the same issue that your image, and some of them does not (the ones that are a bit further towards the center do not).