3D Scanning Question

[Richard Goodwin]

Hi everyone, hope you all keeping sane, safe and well wherever you may be!

I have a question regarding 3D scanning that perhaps some folk on here may be able to help with. I've not done anything like this before but I think there are a few on here that have.

I want to create a 3D image for printing of stillbrew armour for my Chieftain. I have an idea of how I'm going to do it but not sure if it is a valid way!

Two scans will be made using photogrammetry, the first of the Mk5 turret and the second, a Mk10 turret once |I've sculpt it using modelling clay on the existing Mk5 turret. The intention would be to then merge the two scans together to get a 3D image of the armour. Is this idea feasible and would it work?

The plan is to use MESHroom and MESHLab to achieve this since they are both free programs.

Any assistance gratefully received. Many thanks in advance.

[Robert E Morey]

I think that method could work. Scanned mesh files typically take some manipulation and repair to make them actual CAD models. The level of detail achieved would only be as good as your source photos. And even then perhaps not that great for a 3D printed part or parts. I say the better way would be to learn a CAD program to make the models of the parts you want and then use printing or other fabrication method to make the parts. I'm not that familiar with the mods you want but suspect they were add on parts to upgrade capability?
Not sure this helps...
Bob

[AlastairCooke]

Hi Richard,
In my (limited and self-taught) experience 3D CAD and printing works really well if the parts can be created from a set of primitives such as boxes, cylinders, spheres, fillets, pipes or tapers (lofting) etc... or by taking a 2D shape and 'pulling' it into 3D after which it can be sliced and trimmed. See below for the magneto drive housing for the Maybach HL230 which is probably the most complex 3D CAD and print I have attempted to date.

magneto-drive-housing.jpg (93.8 KiB) Viewed 1480 times

The Stillbrew upgrade package is highly three dimensional so may take a lot of time to get construct as you will have to create the surface of the base turret and then the outer surface of the armour then link the two surfaces to form a solid. You may be able to use lofting for this but it may have to be done in sections as the lofting path will not be the same for all areas.

I wonder if you might have more success if you sculpt the 'units' in air-hardening modelling clay and then use these as masters for casting the parts in resin? That way you could possibly provide an after-market product?

Alastair

[Stephen White]

Richard, Alastair has a point. There is an additional variable in your method, which would be difficult to quantify. That is how faithfully the Armortek turret casting replicates the original. It’s pretty good but not precise. Any variation between the real thing and the model would introduce fit issues. I think a better approach might be to use heat sensitive modelling clay which can be warned to work but will act as a solid when cold, from which you could make a casting mould and then a casting. If you still wanted to print the final part, you could scan the resin part…..

[Richard Goodwin]

Gents,

Please excuse my tardiness for not replying sooner! Many thanks for your responses; they are greatly appreciated so thank you.

I have to admit, the thought of profit didn't cross my mind but then again, if others are interested???

I think you'd have to be really good to even contemplate trying to CAD a Mk5 turret and that is well beyond my skill set. However, scanning the modelling clay could potentially be a way forward but only if you chop the final casting into pieces. The same can be said with making a mould from the modelling if thinking about resin. I did have a few alternative ideas to 3D printing and the responses received have provided a new twist on those but I'll discuss these in my blog a little later. Regardless of which way I go, the original post in this thread is a non-starter methinks.

Once again, VMT.

Stay Safe