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Old 05-21-2020, 05:48 PM   #91
popgun pete
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Re: New C4 Gladius speargun

Scubastore are selling the Gladius as well as a carry bag for it and their other guns.
https://www.scubastore.com/scuba-div...05/137473129/p
https://www.scubastore.com/scuba-div...us/137473146/p
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Old 05-21-2020, 05:56 PM   #92
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Re: New C4 Gladius speargun

Another pic.
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Old 05-21-2020, 11:53 PM   #93
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Re: New C4 Gladius speargun

I love to see how before Chinglish became what people laughed at, we had Italish and we obviously still do, haha.
I am not a native English speaker myself and try not to be too anal about this and hey, maybe it is charming. But for a company that charges USD 500 for their cheapest guns, you'd think they could afford a proof reader. Or exhange a gun or two for the service from a spearo with the skills to do it.
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Old 05-22-2020, 03:50 AM   #94
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Re: New C4 Gladius speargun

Maybe a combination of not putting too much emphasis on “feeding the chooks” and “build it and they will come” (with money) regardless.
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Old 05-22-2020, 01:24 PM   #95
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New C4 Gladius speargun



Photogrammetry is not as easy as it sounds. Turns out that Meshroom wasn’t an option for me. Eventually my little brother who is half my age stepped in and was able to produce this model with different software. The CF surface is almost impossible to use with this type of software because it is too reflective and the repetitive pattern of the weave makes the software go nuts.

Anyway I have something to start from but will have to remodel it anyway.

Last edited by kodama; 05-23-2020 at 12:28 AM.
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Old 05-22-2020, 05:02 PM   #96
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Re: New C4 Gladius speargun

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Originally Posted by kodama View Post


Photogrammetry is not as easy as it sounds. Turns out that Meshroom wasn’t an option for me. Eventually my little brother who is half my age stepped in and was able to produce this model. The CF surface is almost impossible to use with this type of software because it is too reflective and the repetitive pattern of the weave makes the software go nuts.

Anyway I have something to start from but will have to remodel it anyway.
Why not dust it with talc to make it look matt?
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Old 05-22-2020, 07:32 PM   #97
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Re: New C4 Gladius speargun

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Photogrammetry is not as easy as it sounds. Turns out that Meshroom wasn’t an option for me. Eventually my little brother who is half my age stepped in and was able to produce this model. The CF surface is almost impossible to use with this type of software because it is too reflective and the repetitive pattern of the weave makes the software go nuts.

Anyway I have something to start from but will have to remodel it anyway.


I didn’t want to put you off but I had a feeling it wouldn’t be that easy.
When I had a go at it, my issue was more to do with translating the mesh into faces in a model in Fusion360. Somehow, Fusion had to drop a ton of the meshes to make it work which resulted in a lot of loss of detail. Maybe I did it wrong but at the time I had to give up.

I know people sometimes spray a matte paint or primer on objects for 3D scanning if they are too reflective but I can see how that’s not as option for you. Unless it could be some water based paint.


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Old 05-23-2020, 12:27 AM   #98
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New C4 Gladius speargun

Actually to get it to this point we already taped the whole surface and placed dots all over the tape. There is a type of plastic which you can spray on and easily peel off which we considered too and supposedly gives even better results.
The mesh is indeed quite inaccurate. I will just use this model to help me create a complete new model that will be very accurate eventually.
There are hours of modeling work ahead to get to something i can work with.

Tomorrow is pool testing day to evaluate the standard setup. Maybe i can make an epoxy mock up of a band raiser and test it. I want to measure the increase in performance first before investing a lot of time. Hopefully the results are positive so i am motivated to plot along.

Last edited by kodama; 05-23-2020 at 01:59 AM.
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Old 05-23-2020, 04:31 AM   #99
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Re: New C4 Gladius speargun

Actually it is quite easy once you know a few basics of how photogrammetry works, however you do need to know a few basic photography skills. You also need to prepare the surface of your subject so it doesn't reflect light as that can cause cavities in your model. The main thing you need to understand is that the Photogrammetry software basically takes clues from the pixels and how the geometry of the pixels change. So you absolutely cannot Crop pictures or otherwise change the geometry in anyway. You also cannot for example take a picture of one angle on the sofa and then move the subject to another place and take another picture and then mix them all up. The software is not intelligent and will not know that background environment has changed. Also remember to use a super high depth of field setting ... preferably around f16 or higher. This makes all parts of the picture in focus and thus gives the software more clues to figure out accurate geometry. This is not always easy as you need a lot of light to do that ... and you can't have a source of light from one direction more than others (like sun in background). Also the ISO setting of the camera must be very low to keep ISO noise to a minimum. These last 2 requirements mean that you have to really drop your shutter speed to where it is only possible to make a crisp steady shot if you use a tripod. In my case I painted over the front muzzle and then drew random lines ... as much as I could. I also built a turntable system with notched marks to allow for a 30 pictures per rotation which I then take at 3 different elevations (90 pix total). With the large C4 gun I used a black background so I could mask out the back in photoshop as if you would keep the background visible and turn the object the software will get completely confused and screw up the results. The turntable system worked really well on a Pathos Handle I did a few years back, but was not so easy to implement on the C4 muzzle as I couldn't cut off the muzzle and had to deal with the whole gun. Fortunately there was a bolt location on the nose and I just used that to bolt it on the turntable. I later found out that this was way overkill and the accuracy I needed to do what I wanted could have easily been adjusted with a not so detailed 3D mesh using Meshmixer.

The 3D model you have already can easily be fixed by using Meshmixer. You basically have a paint brush and you choose if you want to inflate or deflate and choose the surface you want and fix it. If the Left and Right are symmetrical you can save a lot of time by cutting your model down the center and working on one side and then mirroring it. You also need to scale it by choosing an area where you can caliper and using that to scale in Meshmixer. Once you have things how you like them you can take it into Fusion 360 as an OBJ file. In F360 I would not bother to translate the Mesh but I would use the section analysis tool and use a cross section analysis of any part I want to work on. You can use the cross section as a guide to trace several profile cuts ... and then you just use a Loft command to connect between them giving you a solid 3D model. You should be able to reproduce a super accurate 3D model in no time.
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Old 05-23-2020, 08:32 AM   #100
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Re: New C4 Gladius speargun

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Actually it is quite easy once you know a few basics of how photogrammetry works, however you do need to know a few basic photography skills. [...]
In F360 I would not bother to translate the Mesh but I would use the section analysis tool and use a cross section analysis of any part I want to work on. You can use the cross section as a guide to trace several profile cuts ... and then you just use a Loft command to connect between them giving you a solid 3D model. You should be able to reproduce a super accurate 3D model in no time.
Being a photographer for my livelihood I have no problem with the first part.

The issue is that a 3D scan (mesh) can't just be translated into a scultable or otherwise editable format in F360 - which I think is what people expect. Through trial and error, I did indeed end up using the the mesh as a reference and remodeled by tracing the part in many different "slices" and then lofted between them.

Still, fair warning to anyone who thinks you can "just" scan your part, import it and continue modeling in it Fusion.
But with some time/tenacity and a few workarounds, it can work and hey, it's free!
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Old 05-23-2020, 11:30 AM   #101
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Re: New C4 Gladius speargun

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Being a photographer for my livelihood I have no problem with the first part.

The issue is that a 3D scan (mesh) can't just be translated into a scultable or otherwise editable format in F360 - which I think is what people expect. Through trial and error, I did indeed end up using the the mesh as a reference and remodeled by tracing the part in many different "slices" and then lofted between them.

Still, fair warning to anyone who thinks you can "just" scan your part, import it and continue modeling in it Fusion.
But with some time/tenacity and a few workarounds, it can work and hey, it's free!

Yes ofcourse it all depends what you want to do. In my case I wanted to use the bolt locations on my C4 Urukay to make two different muzzles, one a normal classic muzzle that uses the front bolt to add 2 main bands up front and then use the existing band hole for a 3rd band ... this way I get about 10cm of extra band stretch for the same foot print ... something that is sorely needed for that gun to be able to shoot 8mm or 8.5mm shafts. The other was to use the bolt locations and space available for an invert roller carriage. For me all I needed was a 3D shape where I could fit everything on that organic shape.

If you want to bring in a 3D mesh model and play change things around by sculpting the actual model you need to do things differently. You need to convert your mesh to a much more simplified quad where it becomes much easier to push and pull and sculpt things. Best is to use Recap instead of Meshmixer as that is an autodesk product and you can export your 3D model directly as a low resolution quad. You still would need to dramatically reduce the faces though. It is pretty surprising how little faces you need to be able to sculpt something complicated as you can always increase the face count when you want more details. Here is a very simple youtube video that shows you how to sculpt something in 3D with F360. Even a complicated organic shaped speargun shape could be designed in only a few minutes using this method. You just mirror one side and work on it and it automatically generates the other side.

https://www.youtube.com/watch?v=yIoR3SKJdJ4
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Old 05-23-2020, 03:59 PM   #102
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Re: New C4 Gladius speargun

Thanks guys for all the advice. I am used to modeling in Rhino but all the other software Is new to me.

I would love to learn more about that Urukay project. It sounds very cool! Hopefully you will share some of your progress here.

Tried a quick and dirty mock up tonight but it failed.


This would raise the bands already too high lifting the shaft. I will focus on the 3dmodeling first and then print a proper prototype.
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Old 05-23-2020, 11:16 PM   #103
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Re: New C4 Gladius speargun

Is that a threaded brass insert holding the line guide?
If so, perhaps the line guides have threads in them and are loctite'd in place.
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Old 05-24-2020, 12:04 AM   #104
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Re: New C4 Gladius speargun

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Is that a threaded brass insert holding the line guide?
If so, perhaps the line guides have threads in them and are loctite'd in place.

Yes that is correct. Every attachment has inserts and the lineguides are loctite’d.
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Old 05-24-2020, 01:13 PM   #105
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New C4 Gladius speargun

Got to shoot the Gladius 85 in the pool today with its standard setup.
This gun, in this particular length, is a floater. The muzzle is slightly heavier than the handle but not so much that you notice it while aiming. Did some long breatholds and the gun remained very easy to aim or move sideways.

Because it is so light recoil is certainly noticeable but not an issue and didn’t trow off any shots.
Up until 3,5m it shoots like a laser. From 4m I started having problems with band tangles. Unfortunately I mistakingly setup up the mono for a single wrap and when I needed the range for a double wrap a part of it was dyneema. Probably the combination caused the tangles although I am not sure. The gun lacks a line guide and this can often aid with tangles so maybe I will have to add one but I will first try again with longer mono. It doesn’t seem like you want to rig this one with dyneema only.

I got a couple of decent shots at 4+m distance from tip of the spear and had between 3 and 5cm shaft drop with plenty penetration.
All the shots fired with the wishbone on the second last sharkfin.




The prime line 16mm small id band @360% is not too hard to load except for the last sharkfin which made me flinch sometimes.
The band tangles seemed worse when loading to the last tab too with the shots @4m. The mono was attached to the last sharkfin which might have been not ideal. Moved it forward to the rest tab now.

I was quite happy with the performance and accuracy but there is some room for improvement. First solve the tangle issue hopefully with proper length mono and then onwards from there.

All in all a nice gun out of the box at least if the tangle issue is not caused by anything else.

Last edited by kodama; 05-24-2020 at 01:21 PM.
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