Simplify3D User Forum

I have a topographic terrain model (300 x 300 x 50) where I'm finding 'holes' in the top layers because there is insufficient infill support. I was using PrusaSlicer on OPXL5H, but I decided to wake up S3D (since the profiles are now available) and see if S3D can solve the problems. Because of the complexity of the model, the difference between 15% infill and 20% infill is almost double the time. I'm trying to find a way to have a more sparse infill for most of the model, and increase the infill support just beneath the top layers. Support Cubic didn't solve my problems. In PS my experiment was to print the first 2.5mm with grid 15%, and then switch to rectilinear 15%, which halves the spacing between support walls, Although this better supports the solid infill, the rectilinear or zig-zag infills lead to very rough infill as the nozzle continually crosses the prior layers.

So, now onto S3D to see if there are more or different solutions. I've tried multiple dense infill layers and layer expansion, but I'm still ending up with areas where the solid infill is printing 'on air'. I attached a screenshot. Any advice is appreciated.

This is my problem: viewtopic.php?t=11638

There's a setting called "solid infill extra expansion" that will expand the solid infill so that it has more room to grab onto the layers below. It's really helpful if you have cases where the solid layers still look a bit uneven after printing.

Way late, yes, but this might help others.

IIUC, the OP was asking about just increasing the density of the infill just before the top surface. in v5.X this is a built-in feature, allowing n dense infill layers below the top final surface layers. I believe this is the best way to solve your problem.

Thanks, that sounds like the right approach.

For this type of model, I don’t really want to increase infill density throughout the whole print, since that adds a lot of time. What I’m looking for is exactly this: keeping sparse infill for most of the model, but adding denser infill only directly below the top solid layers so the top surface has proper support.

I’ll try the dense infill layers option in v5.x together with solid infill extra expansion and see if that solves the areas where the top solid infill is printing in mid-air.