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Established resin 3d printing wisdom seems to be "lift your model up off the ground, rotate it so as many surfaces are 30-45 degrees to the ground as possible, support all the overhangs, and then if you don't have a ton of supports on there and you're worried it will fall add a few more structural supports"

The problem I've run into personally is, with any kind of detailed model, any way you rotate it you'll end up with a flying heck-ton of tiny overhanging details like rivets, small chamfers, assembly slots and pegs, etc that lead to your model's underside being a huge mass of supports which have a tendency to blob together into a big support that will actually mar the surface detail of the model.

I ran into this recently with a gun arm for a titanicus Warhound I was printing, where the top, both sides, and bottom of the model piece had the potential to be visible, but no matter which way I rotated it I ended up with a ton of corners and details facing downward that just looked like crap after printing.

Eventually, I imported it into windows 3d editor, plane sliced it lengthwise, and rotated it so that the slice plane would be down on the build plate.

I had to add maybe 6 supports total to features sticking out of the sides of the gun, and the most difficult part of the whole model was coaxing chitubox into allowing me to add supports to a model that wasn't floating 5mm off the ground.

it printed up flawlessly, it was easier to get unstuck from the build plate than the pieces I printed with the large flat bases underneath them, and all I had to do was join the piece along the perfectly flat surface of the slicing plane. All I could think was "Why the heck have I not been doing this on almost everything?

Suction force is much higher when you don't try and reduce the cross-section of the model, risking failed prints due to either the model stuck to the FEP or pulled apart layers.

Print lines will be more visible if you print without angling.

I initially came to the same conclusion as you, that adding supports is a huge downside to resin printing. But after a few months, I got the hang of it. Try to learn as much from 3DPrinting Pro on Youtube as you can, he has very helpful videos all around. Also look at the models he made the supports for (there are a few of ArtisanGuild on Thingiverse for free) and learn from it. Bundle supports into trees, keep the supports light (most of my supports are 0.1 to 0.2 mm), add heavy supports where needed and (nearly) invisible.

Edit: All this being said, I also print models from time to time on the build plate if the cross-section seems fine or it's very short print times like flat SM insignias and such.

Also, you want to eliminate any large surfaces that are parallel to the build plate because the resin doesn't 'drain' (as in, roll off of the edge of a slope) in these planes. What you end up with is either uncured pool of resin that'll ruin the surface it's pooling on or you're going to end up with a 'lump' where the pooled resin cured via indirect exposure. This is why it's recommended you angle your prints (in addition to the reasons listed above) in resin printers.

 Hanskrampf wrote:
Suction force is much higher when you don't try and reduce the cross-section of the model, risking failed prints due to either the model stuck to the FEP or pulled apart layers.

Print lines will be more visible if you print without angling.

I initially came to the same conclusion as you, that adding supports is a huge downside to resin printing. But after a few months, I got the hang of it. Try to learn as much from 3DPrinting Pro on Youtube as you can, he has very helpful videos all around. Also look at the models he made the supports for (there are a few of ArtisanGuild on Thingiverse for free) and learn from it. Bundle supports into trees, keep the supports light (most of my supports are 0.1 to 0.2 mm), add heavy supports where needed and (nearly) invisible.

Edit: All this being said, I also print models from time to time on the build plate if the cross-section seems fine or it's very short print times like flat SM insignias and such.

I mean, I'm all about adding supports. But lets pretend for a moment we're printing a cube. If I take my cube and put it on a point like a top, with a heavy support going off that point leading into a base section, versus simply placing the cube on the build plate, you still eventually have to have a layer where the suction force on the build plate has to overcome the full cross-section of the cube adhering to the FEP. The only difference is, with the cube on the build plate, you've got the entire body of the cube attached to the build plate and with the cube on a point, you're pulling against the narrowest point on your heavy support.

Angling most parts, at least the parts I'm looking to build for these titans, actually increases the cross section of the model during the print typically towards the middle, because of how rectangular prisms work.

Another thing about printing straight from the print bed - your usual set up for the prints will have about 30~40 layers of longer exposure to ensure adhesion to the print bed. This set up is typically for the raft when the slicer prepares toolpath. Longer exposure = thicker print "lines", so you will end up with a lip where the print meets the bed, lest you risk the print from peeling off the bed.

Remember to hollow those large pieces, which not only saves a ton of resin, but makes the cross section and resulting suction in a big cross section much less.

 MDSW wrote:
Remember to hollow those large pieces, which not only saves a ton of resin, but makes the cross section and resulting suction in a big cross section much less.

I'd add that it would depend on the geometry & model alignment.

Enclosed negative space on resin prints are big no-no.

 skchsan wrote:

 MDSW wrote:
Remember to hollow those large pieces, which not only saves a ton of resin, but makes the cross section and resulting suction in a big cross section much less.

I'd add that it would depend on the geometry & model alignment.

Enclosed negative space on resin prints are big no-no.

The drain hole is a must and my orientation usually puts it at the bottom (or top depending on your view) and this negates any suction issue.