Dumb Offical Part Question: Lines and Sharp Edges

[Ben Supnik]

Hi Y'all,

Sorry for a whole pile of stupid spec q's, but...

Is there a requirement for official parts that all edges of a part be 'coated' with a line or conditional line?

I read that some programs use the presence or absence of lines to determine which mesh vertices should be smoothed across triangles, but I didn't see anything in the part authoring spec about the requirement that lines be present.

Is having lines on the edges something so basic and obvious to everyone that it didn't need to be stated? :-)

Thanks!!!
Ben

[Michael Heidemann]

Short answer - yes

Each corner should have an edgeline. If primitives meet (triangle or quats) at an angle to imitate a round structure you should put an optional line there.

[Travis Cobbs]

Interior curves (where the curve can never trigger a conditional edge line that is visible on-screen) aren't required to have conditional lines on them. Many do because of LDView's smoothing relying on conditional edge lines. Many others do because they use primitives, and all curve primitives are allowed to be interior or exterior, so contain conditional edges. All creases are required to have edge lines (line type 2, color 24).

[Ben Supnik]

Thanks guys, and Travis, thanks for the link to the LDView exporter code.

I will look at line-based smoothing for BrickSmith...it seems that the line requrirement for sharp lines might be stronger than the conditional line requirement for non-sharp lines.