Today we're going to be creating a 3d model of my house using this drone now we've talked a lot
about drone surveying and aerial mapping but today we're going to be exploring 3d modeling
of existing buildings or features that you can capture with your drone in order to do this we're
going to be flying our site in three different methods the first method is aerial mapping which
you're probably very familiar with this is where the camera of the drone is pointed downward in
a nadir position at 90 degrees providing us with a clear shot of the aerial perspective
from the drone the second type of flight we're going to be doing is a low oblique low oblique
shock usually tilt the camera angle between 45 and 60 degrees this allows us to get a clear shot of
the building from far away and usually at a higher altitude it also means that there is no visibility
from the horizon which is why we call it low oblique now the low oblique angle is a relatively
safe flight you're flying 100 feet above ground level and you're usually about 50 feet away from
your point of interest so in our case it'd be my house the flight path would either be a circle
or a square around the point of interest and you would take an image every 10 to 20 feet
now the last type of flight is going to be the high oblique angle the camera angle on the drone
tends to be pointed at 0 to 35 degrees and the drone is about 10 to 30 feet above ground level
i know that's really low the objective of a high oblique flight is to capture as much detail
up close and including the horizon in our shots this is usually because we're trying to get all
the detail of the building all the way to the top and sometimes underneath notice how the roof up
at the top here covers part of the siding so we can't see this unless we're up close and doing a
high oblique flight by combining all three of these flights we're going to be producing the
highest level of accuracy and highest level of resolution for a 3d model of my house
alright let's get started first thing we'll do is set up the cones
set the drone in the middle and power on the drone
all right so we've got the flying path for our aerial flight here's the house and we're flying
just over the house we're flying at an altitude of 25 meters above ground level at a speed of two
meters per second if i go down here to camera settings you can see that the gimbal angle is
set to negative 90 degrees so that's going to put it in nadir mode which is pointing straight down
we'll go to advanced settings and i've got the horizontal and vertical overlap set to 85 degrees
just so that i can capture as much detail as i can we'll hit save save we'll name the mission
aerial done and confirmed all right everything here looks good i'm going to click on start okay
and slide to execute start operation
there we go it's capturing images pointing straight down at 90 degrees very good
there we go operation complete and now it's going to be landing
now that we've flown our first aerial flight it's time to fly our second low oblique flight
okay so i've now set up the locations for all of these shots that i want to take i tried to spread
these out as equal as possible and have them point in the center towards my point of interest under
the root settings here i have some options i can play with but the biggest one that i want is the
cruising speed i want to drop this down to two meters per second i want this to go nice and
slow there's no need to rush because if we rush we're gonna get blurry images and then data that
we can't work with i'll hit x save override the task all right and now we can hit start it's going
to ask me for relative height or absolute height i'm going to choose absolute height
and i'm going to slide to execute start operation
so as you can see the drone is quite far away actually
and it's flying in a circular path around my property now it's stopping at every point that
i told it to stop at so that it can capture that image with full clarity from what we can see on
the controller it's at point number four right now it's captured the image and if we look at the live
view there we go it actually isn't as far away as you might think but this way we're
able to get as much detail of the house um at a high and safe angle okay now we're here at the
front of the house this is at point number eight now we are going to point number nine
now that we've flown our low oblique flight it's time to fly the third and final high oblique
flight all right so i flew the drone around and i was able to set waypoints for everywhere
that i need to be i made sure that i'm clearing everything and that there's nothing in my way
nonetheless having obstacle avoidance will be helpful and i'm going to be maintaining
a very clear visual line of sight at all times so i'm not going to be able to give you fancy
camera angles while i do this under the root settings i'm also going to drop this down to
two meters per second we want to go as slow as possible give us as much time to work with this
no rush we don't need any problems and you might notice here that we are flying into my neighbor's
properties it's very important that you let your neighbors know if you're going to be doing this
i already have i'm very good friends with my neighbors they know they are
okay with it so i have consent to fly over their properties and with that i'm going to hit save
i'm going to override the task start absolute height and slide to execute
all right and as you can see we're only 17 feet off of the ground so it's very important that we
pay close attention to the drone at all times even though it has obstacle avoidance it's still very
smart to keep an eye on it my finger is going to be really close to the pause button just in case
anything were to happen um it should be all right the beeping means that there's a tree within 10
feet so 10 feet we should be all right as long as the beeping doesn't increase
all right and it's gone away now we've gone away from the trees these are the positions
that i selected so i know that this is going to be a clear path right here and the drone is
about to get out of my line of sight all right i'm going to go ahead and pause the mission here
and that's going to give me an opportunity to go to the other side and
get a cleaner shot with my eyes to make sure i have full visual line of sight
okay we're closer now the drone is up there i'm going to go ahead and hit continue
the drone's going to resume its operation
it's looking good
still got good line of sight everything looks good all right i'm gonna go ahead and pause it right
here and let's go to the front of the property okay drone's up there i'm gonna hit continue
it's gonna keep taking pictures they'll try to get out of the way
and the drone is behind my camera right now i'm gonna go ahead and pause one more
time so that i can go inside and get a better visual sight okay hit continue
drone is going to take a few more shots it's got one more position
all right there we go i'm gonna go up so we get far away from everything
and i'm gonna bring the drone back home
all right we've safely completed all three of our flight missions now we're going to export all
this data and head into the office i'm going to show you how you can process all three data sets
to create a 3d model before we get started i want to take a look at all three of the flights
and analyze all of the images this right here is the first flight this is our aerial flight
where the camera angle was pointed 90 degrees in a nadir position
we can see all of the images very nice very crisp and definitely a down bird's eye view i like it
and this will be a great foundation for our 3d model next we have our low oblique flight and
not many pictures however we're going to get a lot of good data out of this we've got every angle of
the house very good i like it a lot and the last flight was the high oblique flight and there's the
images you can see we're a lot closer to the house and our altitude's a lot lower there's me and
yep i like that this detail is going to make our 3d model pop and be super helpful
okay so i'm going to be utilizing a software known as PIX4Dmatic. PIX4Dmatic is a photogrammetry
processing software that allows you to import images and create several outputs
this can include point clouds ortho images dsms 3d models everything that you would
need for your photogrammetry projects and it's going to be the software that allows
us to create a 3d model of my house here we have PIX4Dmatic opened and the first thing
i'm going to do is create a project name i'm just going to call it 3d model home let's start
and on the right here it tells us to drag and drop images or folders here's the data i've got
all three data sets and i'm going to select them and drag them into the software and the
software automatically knows where these images are based off of the geo tags that were captured
with the drone and this looks good it looks like we've got a lot of coverage on the house
very nice we can also see all of the images over here on the right side now you don't need to
set a coordinate system for 3d modeling a lot of times the client really just wants a relative
model in an arbitrary coordinate system their main focus is to have accurate measurements between
points not necessarily having absolute accuracy in positioning your project in the world however
it doesn't hurt to identify the coordinate system and PIX4Dmatic makes it really easy to output your
data in a specific coordinate system so for me i might as well output this data into state plane
coordinates to do so i'm going to come down to the bottom right and click on this pencil down here
it's going to ask me what my horizontal coordinate system is i'm going to say nad 83
michigan south and the first option is the correct option for me the vertical coordinate system and a
88 there we go and the geoid geoid18 all right i'll hit apply and the base map will reload just
want to make sure that our base map is correct we will see hopefully the same exact thing again
okay there we go we have the exact same thing now if you had ground control points um you could
import those coordinates and do geo referencing i don't have any ground control points because
again i'm not really focused on the mapping i'm more focused on the modeling for this project
in a future video i'll show you how you can do geo-referencing with matic but for now let's
get into the processing up at the top right i'm going to select the processing options button
and i can select a template right now it's set to knee deer which is probably the most
ideal for aerial mapping but because we're doing modeling work i'm going to select this and switch
it over to oblique now aside from the processing template we also have a calibration template
these are a bunch of preset templates that Pix4D made and so i'm going to start
out by using the modeling template since this is a 3d modeling project
the pipeline basically asks how much you want to trust the geotags that were provided by the images
if you're using a standard gnss drone one that doesn't have rtk i would leave this on standard if
you are using rtk then you can select and change this over to trusted geolocations and orientation
image scale i'm going to keep this set one to one because i want the full image resolutions
to be used the key points these are going to be the prominent features that are extracted
in the point cloud you can limit the number of features that are extracted to basically manage
the data set size but if you keep it set to auto PIX4Dmatic won't limit the amount of keypoints
that it creates and the internal confidence this is basically asking how much do you want to allow
the software to move the image to fit it into the model if you keep the confidence set to low
then you can allow the software to move it more i'm going to keep this set to low just so that
i allow the software to shift the images and fit them properly and create the most accurate model
all right cool now densify is the point cloud and this is what's going to be used in order to create
a 3d mesh of our project i'll select densify algorithm you have the standard algorithm and
the accelerated standard is going to take a little bit longer but have cleaner work
accelerated will be faster and it probably won't generate as many points
i only have 66 images so i'm going to select standard and try to get the cleanest work possible
image scale i'm going to keep it set to half the density we can set it to high optimal or low
this is basically how many points you want in the project i would just keep this at optimal and then
the minimum matches which basically asks how many matches between images of a feature are required
in order to create a point having three images is pretty good that way you won't have too much
noise and you will have a decent amount of points that you can work with noise filter will try to
clean out any noise that comes up and then the sky filter because we used high oblique imagery
the horizon was a part of the images so i'm actually going to turn on the sky filter
next we have the mesh and i'm going to enable the mesh and i can select on the texture size i'm
just going to keep it at the default and then the maximum number of triangles these are the 10 lines
we have a maximum of 1 million triangles which is going to be more than enough for our project
i have some additional options like creating a digital surface model and an orthomosaic image
so if i was doing mapping work i could output these as well but i am going to just focus on
the densified point cloud and the mesh because i'm only looking for a model down here i have outputs
i'm going to output the quality report the point cloud and the mesh now that we're done defining
all of our parameters we can begin processing and start now depending on your computer the amount of
images you have and the parameters that you set this could take anywhere between a few minutes
to a few hours all right now that all the images have been processed let's take a look at the data
here we have the point cloud enabled and i can zoom in here and take a look at our site
now some areas like the right side here there's definitely a lot of missing data
and that's just because the drone was just so close to the building and this is one of the
downsides of using a drone to take high oblique imagery you just don't have that
much control over where the drone is and you're very concerned with obstacles so you're forced
to compromise the quality of the image for the safety of the drone now since back over here we
had a lot more room to work with the drone so the back has lots of points and lots of details
the back portion of the house on the right side is fine however the right portion of the garage isn't
and again this is the image that was used so lots of missing data there again we had
to compromise we couldn't get that close and had to stay back a little bit now that being
said there is a way of doing this using your iphone and capturing data on the ground now
if you click on this video right here i'm going to show you how you can take your drone images
and combine them with your iphone images to create the most accurate 3d model