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Author Topic: FR: Transparent 3D simulated water surface for underwater scans  (Read 1175 times)

CheeseAndJamSandwich

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Could we have simple 3D semi transparent water surface that we could turn on, to aid in visualising underwater scans when in Metashape?

I'm scanning underwater dive sites that go down to about 50m deep, but mostly 10-20m...  But looking at the models, unless you can recognise features and know their size, you simply don't get any cues to the sizes, depths, scale of the features/model.  What you're looking at, be it a coral formation, rocks, bommies, etc, could be the size of a shoe, or the size of a house, it's hard to tell.  It's slightly easier with wrecks, as we know roughly how big ships and their features are, but still you don't get the depth cue, which is important in itself (us divers need to know the depths).

Obviously, the ideal solution is to take the model into Blender, or similar, to create the underwater scene, where it could be made to look absolutely amazing and realistic.  But what I'd like is just a simple water surface to aid in visualisation within MS.   Plus learning Blender looks fairly involved!

Could we have an option in settings to cater for us underwater folk?
The water's surface would simply lie on the x,y plane, at z=0.
The size of it could just be to the extents of the grid size, which is already set in settings.
With MS Pro, the -z values from the GCP would set the model depths correctly... but i only have Standard, so i use the grid trick, setting the grid to meters and move the 'object', mesh to the correct depth, and to set the scale.  Works great.
The simulated surface itself could just be a simplified 3D wavy surface that resembles water enough.
It could have tint to it, so blueish, or greenish, so that it looks like you're looking thru water.
The simplified water surface could have some basic parameters that we could set, to set the wavelength, wave height, colour tint for the surface.  This would then cater for different seas states at that location, adding more size/depth cues.
Ideally, the volume under the water could also have the volumetric feel to it, but that's probably going to far, lol.

Even the most basic of simulated waters surfaces would be so, so helpful.

Cheers.

EDIT:  Oops, posted it in General by mistake... Should have been in Feature Requests.  Sorry.
« Last Edit: August 28, 2021, 09:29:57 AM by CheeseAndJamSandwich »

CheeseAndJamSandwich

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #1 on: August 28, 2021, 09:46:48 AM »
For example:
Here's a couple of images from one of our dive sites models.
Without the grid showing, you don't have a clue how deep you are at all, how bit things are.
With the grid, you get a feeling for how deep things are.

SimonBrown

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #2 on: August 28, 2021, 06:12:42 PM »
I do a lot of underwater work (https://deep3d.co.uk) but I must confess the idea of a surface hasn't really been something to consider - for me at least - even when working with coral data.

Are you including a scale bar or anything in the scene that can act as an indicator of scale?

This may be something more suitable in the VR/game engine world perhaps?

Unless I'm missing something?
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CheeseAndJamSandwich

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #3 on: August 29, 2021, 12:03:35 AM »
I do a lot of underwater work (https://deep3d.co.uk) but I must confess the idea of a surface hasn't really been something to consider - for me at least - even when working with coral data.

Are you including a scale bar or anything in the scene that can act as an indicator of scale?

This may be something more suitable in the VR/game engine world perhaps?

Unless I'm missing something?
I've been following your work for years.  It's been a big inspiration to me to get scanning down here!

What we're missing most, is the ability to put the underwater scans into context... That it's actually underwater...  And for scuba diving, we need to know the depth.

If you take your Acorn (https://skfb.ly/opFZ7) and Stalwart (https://skfb.ly/MGK6) models, to a layperson, they're basically the same, but one is a bit green...
I know the Stalwart is underwater, as I've swam around it at ADAC!  But the model doesn't tell you where it is in relation to the surface.
And for your other wrecks, some of them are shallow, some of them are deep, but we cannot know how deep from the models.

For my dive site scans, we want to use them for dive site briefings, and especially at 'Manta Point', where we hang out with all the mantas for an hour, the focal feature of the site is the big bungalow sized cleaning station rock near the cliffs, it's where the mantas congregate/concentrate... This rock is only 4m deep on the top, 11-12m deep around it.  So any 'map', model of it absolutely has to have the surface represented somehow.
The manta point model just doesn't work well enough as a map without that surface being there.

RE: Scale bars...
It's was easy for me to find two notable rocks that were 10m apart and to get their relative bearing, and also the depths of some of the big rocks, so using MS's grid, i've set the model 'depth', scale and orientation to an accuracy that's easily good enough (plus we have a 2.5m tidal range of course).
Adding a scale bar to the 2D captures I'll make to print off with be easy to do, along with a compass of course...  But I'll mostly be photoshopping in divers and mantas that i've accidentally scanned, or that i'll photograph in place specifically for scale bars.
I've attached a couple of captures from my Blue Corner dive site scan.  The first jus shows some rocks... The second, with my mate Jason in it, taken from one of the scan's images, photoshopped in, totally gives you a feeling of how big those rocks are..  (Sadly there have been no Molas there yet during my scans)... So this gives us scale, but no context of the depth.
For 3D models, fly-thu videos, the best scale bars will be if i can add 3D models of mantas, and divers to it.  That's obviously a job for Blender, and a tough one for me.  But again, if i had a representation of the water's surface, then that already adds most of the context to the 3D model, video fly-thrus of it.
Turning on the grid makes a huge difference, but it's a grid.  It just gets in the way a bit. No matter what transparency you set.

When doing aerial surveys of a building, town, terrain, we can infer the scale of it just from the familiar features present, and we know that we could walk around on the ground show, as we're stuck in the '2d' world...  We simply don't care what the altitude is of that site, it's not important...  But underwater, sometimes it's just rocks, coral, so we need to be given something to scale off of, but we mostly need to know how far underwater it is, especially if it's not that deep.

Almost everything we scan underwater needs to have depth cues, context to the surface we're below.
« Last Edit: August 29, 2021, 12:09:29 AM by CheeseAndJamSandwich »

CheeseAndJamSandwich

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #4 on: August 29, 2021, 12:47:09 AM »
Here's a quick-n-dirty fly-thru animation i did of one of the swim-throughs at the Manta Point dive site.
You simply don't get any cues that it's underwater, its scale, how big those rocks are, or how deep/shallow it is.
https://youtu.be/P9UX-PV5yhs

In reality, those rocks are about 10m high, and are only 5m deep on the tops.  So when you're swimming over to them, you can see the surface above them.
These cues are all missing.

SimonBrown

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #5 on: August 29, 2021, 11:52:28 AM »
Scale - in the Standard version its not possible to add anything quantative or precise (Pro version required) but for scale we can add something everyone recognises.

A human.

Check this out:

https://sketchfab.com/3d-models/underwater-wreck-of-hm-submarine-e-49-40d1c47a4d7447feb42e643cea895d7a

Its the E49 wreck in Balta Sound. This was the first attempt at adding human scale by including a diver.

There are two divers in the SS Thistlegorm model, on the port side at the stern. Trouble is, the model is so massive they become lost. But they are there, in the ortho photo:

https://dronelab.io/map/public/viewer/e5a43bc124a34ea2b4bcfd1d2843463e

So perhaps a human would help? They need to remain very, very stationary and work quickly to capture them.

It won't help with the surface, but the fact they are in scuba gear will add underwater context too?

Glad to know its been inspiring.
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CheeseAndJamSandwich

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #6 on: August 29, 2021, 04:05:08 PM »
I saw your 'scuba human for scale' sub model.  Works great!

Just using the Grid method, as Alexey described in a post a while ago, I'm getting the model within 10-20 cm per 10 meters...  I just took the tape measure down and found two rocks 10m apart.  But any measured, identifiable pair of features work great.
So setting the scale is actually 'easy' in Standard.
Using a scuba diver or in our case, a manta ray or two, easily gives us the scale cues, especially for 2D captures, i can 'shop them in easy peasy.  For 3D, i need to find out how to make MS include all/most of a scan photo, instead of filtering out the moving fish/diver...  I guess there's a way to do this???

But anyhoo...

What I'm after here is that water's surface.
Especially up on the cleaning station at Manta Point, you've got 4m of water column chock full of mantas sometimes... The surface is always in view when you're there watching them.  So it needs to be there in the 3D representation of it.  And some of the rest of the site is only 8-10m deep, so it can be a very shallow dive, depending on what the flappy fish are doing that day.

If i ever work out Blender, i'll let you know how...  Otherwise if you know someone, get them to throw one of your wrecks/APCs/choppers into an 'underwater' scene, with the water's surface set at the right depth, and i bet it'll transform the visualisation of your models.

Here's a clip of a fairly good number of mantas on the cleaning station, though it was a shite vis/green day... And yeah, sorry about the plastic in the rest of the vid. Yep, i'm that #rubbishdiver.  :-[   I'll try and upload some better footage to show it off better.  It's lovely when it's good vis.
https://youtu.be/SBHNjdVMgkM?t=17

SimonBrown

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #7 on: August 30, 2021, 12:11:03 PM »
I saw your 'scuba human for scale' sub model.  Works great!

Its a singular, recognised unit - "human" - that most can relate to.

The vis in that manta video was the kind of conditions we dream of here in the English Channel...

The surface could be added as a chunk...and then moved to suit...but it feels more like a viewing/immersive/VR application rather than for the authoring tool - there is some work going on with a game engine and one of my models that is likely to deliver far more than the raw authoring tool such as Metashape could deliver.

I will share it if/when I can.
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CheeseAndJamSandwich

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Re: FR: Transparent 3D simulated water surface for underwater scans
« Reply #8 on: August 30, 2021, 02:21:18 PM »
I saw your 'scuba human for scale' sub model.  Works great!

Its a singular, recognised unit - "human" - that most can relate to.

The vis in that manta video was the kind of conditions we dream of here in the English Channel...

The surface could be added as a chunk...and then moved to suit...but it feels more like a viewing/immersive/VR application rather than for the authoring tool - there is some work going on with a game engine and one of my models that is likely to deliver far more than the raw authoring tool such as Metashape could deliver.

I will share it if/when I can.

Of course, the real pukka water surface would be added with blender, etc... for 'publishing' purposes
But as underwater photogrammetry is a not uncommon use for MS, a simple surface would be very helpful to a lot of us...  In a similar way that we can view the models in perspective mode...  it's not necessary, but it make it look correct.  With UW models, a simple surface being there will help make it look right.

I look forward to seeing your project.
« Last Edit: August 30, 2021, 02:23:10 PM by CheeseAndJamSandwich »