Getting rafts to properly support large prints on a small bed

[bovi.ret]

I'm still pretty new to 3D printing (like only a few weeks in) and I've already run into something keeping me stuck. I'm working on a big model jet that I had to rotate and scale down to fit my Adventurer 3 Pro's 150x150 glass bed. That part was fine, but when I went to slice it, I set it up with a raft and supports expecting the raft to match the footprint of the whole model.
Instead, the slicer just threw down a basic raft under certain areas and not the full outline. Thrice now the print has gone sideways because the supports didn't have enough foundation. I was hoping the raft would basically mirror the shape of the model so everything above it would be locked in, but that doesn't seem to be happening.
Is there a way to force the raft to cover the entire footprint of the part (or at least the supports)? or do I need to approach this differently like manually adding a base in CAD or using a different setting? any tips would be awesome
Thanks a lot in advance

 

[allproto54]

Don't sweat it, that happens with new printers and you're thinking about it the right way. Your slicer's not giving you a full raft because it's only putting them where it thinks the model needs one, which is usually just under the initial supports or the model's footprint. The problem is that it's often not enough, especially for big parts on a small bed. The easiest and most reliable fix is to manually add a thin, flat base to your jet model in your CAD software. Just create a simple shape that matches your print's full footprint and a few millimeters thick, then merge it to the bottom of your model. When you slice it, the printer will treat that new base as the first layer, giving everything a solid foundation.