On Fly Offset?

[lrdsatyr8]

Something I've often wondered about over the years is the setting "On Fly Offset" in the booleans submenu. I assumed it was how many units the cut would take off outside of a boolean subtract operation, but honestly I have no idea what it's used for. I do alot of 3D printed parts and usually if I've got two parts that I need to fit together like a peg and a hole, I figured by setting that to like 0.5 it would allow the two parts to fit together without any problems, but I'm finding it's not the case. Does anyone actually know what that option does? Thanks!

[trueBlue]

The only information in the Manual:

On Fly Offset: Defines the minimal distance between two applications of an operation. A smaller value
will create more faces but have a smoother appearance.

[lrdsatyr8]

That about all I could find on it too.

I'd like to find a way to do a boolean subtraction of two objects so that when 3D printed they either fit together snugly or are able to move freely against each other. Any ideas?

[trueBlue]

It has been said that Model Booleans are not the greatest.
It has also been said that Workspace Booleans are better!

[Finis]

Make the subtracted object slightly larger. Then the hole will be slightly larger to accommodate the part that goes into it. Just an idea. I know nothing of 3D printing.

[borgcone]

I don't have more information about the On-Fly-Offset parameter than trueBlue: tsxAPI66.doc and tsxBoolean.h in tS 6.6 SDK (i.e. for tS 7 Model side) don't have the definition and explanation of the parameter (they say only ones for undo, keep-drill, and delete-edges). The tS 6.5 PDF Manual (not 6.6) also says almost the same with the sentence that trueBlue quoted. The tS 5.1 doesn't have the parameter in the option box.

As you know, each of most things in this story is DISCRETE and has ERROR.

Discrete things are: The position of printed minimum unit per printer/material/quality-mode, Accuracy of Boolean operations per algorithm/other-params/tS-versions, Difference between ideal cylinder and n-sided prism (that has n longitude lines), and the tS's coordinates themselves (4 byte float, etc.).

Accuracy errors are caused by: Limit of printer's spec, deterioration of printer/material, Room temperature, Distance between ideal curved surface and polyhedron surface, Mountain folds and valley folds judgment(guessing) at triangular dividing of a 4-points facet surface, Importing optimized (rounded) data from file with other format, Cumulative error by repeating addition of value with tiny error e.g. adding 0.1 to something 2^30 (about 1 billion) times will cause an error of more than 1%, etc.

The images below are an 2D example of a cylinder (replaced in a 16-sided prism to emphasize corners) and a 3D example of mountain/valley fold of a small facet.

... need to fit together like a peg and a hole ...

If I were (and had enough time for that), I will write a original script for model side (or older tS version) that searches for the points (coordinates) that have minimum clearance between two objects. If the objects are solid of revolution, also needed to rotate a bit around the axis. For that, However, unfortunately tS Model side's memory system does not allow me to do such a large amount of calculations fast.

Using tS's Collision Detection API function tsxPhysSimGetCollide() in the script also may or not help. The spec is much veiled in mystery and the function does not seem to be so applicative and consistent for daily uses.

Moreover Model side's Boolean operation often causes tS crash or infinite loop (especially in case that some points or edges are too closed to between the drill and the target even if a low-poly object). As a result, in practical terms, I must usually repeat a cut-and-try cycle (load scene, change param/location, save to another file, Bool, crash, load...).
Related topic by Johnnycrash (but mainly for tS4):
"New to TS7.61 (6.6) - Need some hints/help"

I'm not familiar with tS 7 Workspace side's script (1D).