I'm not sure if this goes in my European thread as I'm not sure how far Europe actually extends Eastward........But I don't have a global thread so it might as well go here.
Something a little more left field, well a lot more left field, a long standing and niggling itch needed scratching, it's also a good test to see how the Saturn 2 8K copes with large (very large) objects. After much testing I've nearly got the support structure and orientation dialed in, this one was almost perfect but got damaged whilst extracting the support structure.
I'll keep it as a paint and weathering test pig and as a basis to work out how to smooth some areas that need doing post processing.
The large objects with broad rounded faces has thrown up something new, nothing to do with the resin, machine or artwork, it's to do with the export model, Autocad doesn't make perfect round faces, instead it makes them from many small flat faces (lands). Normally this is no issue on smaller parts as the lands are so fine as to be near invisible, the larger the part the bigger the lands, Autocad seems to keep the same number of lands to radius when you scale up, rather than keep them the same size and add more to make the surface smoother.
It's quite a big problem as you need to post process them smooth so you need to make sure those surfaces do not have any surface detail. The worst areas are the cant rail radii and the nose corners, it's even present on the nose front but not the buffer beam as that's three flat faces. On the cant rail are two sand fill ports (sans lids) and these might have to be changed from raised boxes to hollow square holes that the enclosure drops into and the gap sealed up. The same applies to the nose, I might have to make the star and MU socket groups are separate parts fitted later.
Essentially it's a Soviet block dual unit electric engine, with 9000 units to choose from spread over what was the whole of the cold war empire and dozens of classes there are one or two variations, this one being one of the semi permanently coupled triple sets. Once you have the basic cab and shell then the rest is down to detail differences, vent placement windows styles and roof fittings. Even then you can carve the nose off and fit the later more angular ones to model those later classes.
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There's still a little kick up at the base toward the rear so I need to fine tune my angles and support structure, problem is, at 50 microns it take over 16 hours to churn out and eats a ton of resin, I can just squeak four cab units from one litre of resin.
The other down side is the resin, FNG has a tendency to separate and marble quite quickly, so 16 hour prints run the risk of the resin changing properties during the process, it'll be worse at 30 microns and I've no idea how it would cope with a 10 micron run which I may need to do to ease the layering on the cab roof front and nose top.
I've only smoothed (very roughly) the LH side of the model so the layering is still evident on the RH side if you look closely. The 3D model is a bit rough on the cab top corners as Autocad doesn't so this sort of thing well, they'll need smoothing better on later runs but I'm not overly concerned as I'd like to use brass strip to replicate the gutter eventually; that's going to be fun to form and fit and I may just not bother and 3D print a small ledge on there and be done.
so before I can even try it I have to upgrade the PC......not happening, not for the foreseeable future.
typically I work in RAW and they're around 22 MB.