Reducing the size of the Preform Base

I am about to print a large threaded disc with a hollow centre…
My prefered orientation is as per the attached image but it uses a huge amount of resin in the centre of the disc where the base is not needed.
Are there any techniques I could use to reduce/remove this unwanted part of the base.
I will probably end up orienting it vertically!

There was a version of preform some time back that would have left that interior area free of support material, not sure why they changed it as I never had any problems with it. Probably because it uses more material (with my cynics head on! )

I can understand your pain here. In this case, I would probably orient it vertically as well. Alternatively, I might try reducing the thickness of the raft to save on material, depending on the resin type.

The raft generation code won’t make a hole in the middle, but there is one trick to getting what you want. If you delete a few supports to leave a path from the outside to the inside, then you’ll get a “C” shaped raft, like this:

You need to be very careful not to remove too many supports though. As you can see from the red shading, I’m pushing it in this example.


Ah. Thanks mgarrity.
Just tried it and I can just about make it work.
It saves a huge amount of resin!!

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that’s a cool trick :slight_smile:

The code that makes the beveled edge that you use to pry the raft off the build platform wraps around all of the supports, and doesn’t know how to add holes. That means that for this trick to work, the gap you leave has to be a little more than twice the width of the chamfer. I would usually put the gap on the high side, like I showed above, because the model itself should be strong enough to add some support by that point.

Thanks @mgarrity, not sure how I missed this discussion. That is a cool trick, I did get my item to create a ring shaped raft in the past but I wasn’t sure how I did it. Now I know how to force/trick it.

If for some reason it doesn’t work or someone might be timid to remove too many supports, I like the idea of putting one item inside another. It allows me to print two items at once where one might think it is not possible.

Yes, it’s good to have a collection of these tricks in your toolbox. Your two items at once approach is good because you know you’ve got plenty of support.

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