Preform - Automatic Orientation issues with models

Issue 1: Large Files End Up Out of Bounds
On larger models, I’ve noticed that the automatic orientation of files almost never seems to land the item wholly in the building zone of the platform. I’m often able to orient them and add supports by hand in Preform – and successfully print. This leads me to wonder why it’s so often the case that Preform seems to prefer an illegal orientation (which definitely cannot print) to a slightly-less-than-optimal one that can.

Suggestion: Allow Preform to Present an Alternative Layout that Fits
I’d rather have Preform try and give me alternative options (with appropriate warnings) that actually fit on the platform, as opposed to calculate supports for something that won’t.

Issue 2: Inconsistent Placement of Model Makes it Hard to Place Drainage Holes

As I’ve been learning the ropes with my Form 2, I’ve noticed on more than one occasion that a .STL file that I’ve hollowed out and added drainage to in Meshmixer, gets re-positioned in such a way that the drainage holes are badly positioned. (IE: Flipped so that they’re on the top of the figure being printed, for example.)

I’ll go back into Meshmixer and move my drainage holes, only to find that Preform will once again manage to flip the figure in a different way that the drainage holes are irrelevant and allow resin to pool inside the cups. (Maybe I’m doing something wrong?) Short of making the model loaded with holes, I’m stumped on the best way to tackle this.

Suggestion: Make It Possible to Add Drainage Right in Preform
It seems like I cannot necessarily anticipate where Preform will determine the ‘best orientation’ for the model will be prior to printing, and the .form file cannot be edited in Meshmixer (at least to my knowledge) – it’d be handy to be able to add drainage holes to the print directly in Preform once the supports have been added.
That being said, if you are able to do that, it would be excellent to be able to perform the hollow and drainage editing that I’m currently doing in Meshmixer entirely in Preform.

Sound like you’re using the automatic orientation a lot, is there a reason to do so ? I think most user past absolute beginner will orient their prints manually, as its very unlikely the automatic orientation will get your part with supports where you want them.

If you’re adding drainage holes beforehand, you must already have an idea on how you want the print to be oriented, I suggest just manually orienting the part like you imagined it.

If you’re loading the file in preform, hitting auto orient, go back to meshmixer to alter the model and then re-hit auto orient the result is almost certainly going to be different. If you really want to use auto orient, then do it once, modify the STL with meshmixer without closing the file in preform (there is no link between preform and the source STL) based on Prefom’s proposal, then go back into preform, right click on the model -> replace -> select the STL again. This will replace the original model with the altered one while keeping the orientation.

As for the issue 1, see my first paragraph. TL;DR : don’t use auto-orient if you want to really control the output of the printer.

The auto-orientation button in Preform will cycle through different orientations until you find one you like.


Thank you so much for that tip; very much appreciated.