Models set into the base by a small amount

[MartynB 0]

Hi, hopefully somebody may be able to help with this but its driving me nuts. I am running the latest version (Cura 3.1.0) and have recently been noticing that my models are set into the build plate by a small amount. It is only a small amount, but I am getting flats on models where there shouldn’t be any. I am having to turn off ‘automatically drop models to build plate’ and adjust the model manually. Does anyone have any ideas how I can fix this? I have included an image showing what I am getting, hopefully it is clear. This is not how I would actually print this part but shows well the section that is cutting into the build plate.

[kmanstudios 747]

It all has to do with how the program that generated the model and Cura interact concerning pivot points, I believe. It also may have to do with how the program is generating the geometry and then interpolating out to mesh if it using math instead of mesh for generation purposes.

[MartynB 0]

Thanks for your reply. Not sure why this is just happening now though? I've never had this problem before. Surely Cura should just detect the edge of a model and with ‘automatically drop models to build plate’ switched on, sit the model on the build plate like it always used to?

[kmanstudios 747]

I am not sure what sort of algorithms they are using to detect edges/vertices intersecting with the buildplate or if they tweak it between versions, or if some other code is creating a disturbance in the printforce. But I find it is a bit of a hit or miss situation. It definitely could use a bit of improvement. I am ultra anal about pivot points and 0 Zed locations of surfaces. My 3D packages do not work in math, but pure mesh generation, so, If I put something at 0 Zed, then it should stay at 0 Zed and not sink or float. Not always off, but enough to be annoying.

 

Edit: Just occurred to me that they may be using a bounding surface to generate the collision detection and that could be why it is a bit sloppy. It may not be true edge detection after all.

Edited December 20, 2017 by kmanstudios