Hello,

I noticed that the box primitive have different point normals between 15.5 and 16. Is that normal? and if so, why did it change?

Thank you.

What your looking at in 16 are not point normals but vertex normals.

I can't say more as to why, but I was just playing with 15.5 and 16 and the display behaviour is different between the two.

If you go to display options ( if you haven't already )…you can check off/on for point, prim and vertex normals.

It seems in 15.5, you only get vertex normals if the box has the add vertex normals checked off. In 16 it doesn't matter, you can display vertex normals whether that check box is ticked or not.

But then again, in 15.5 if you look at the spreadsheet or middlemouse click the box, there are no point normal attributes; But you can still display point normals on or off.

In 16 I just put a wrangle after the box with @P = @N; Then I was able to get the point normals displaying like what you have with 15.5

Under display options, you can switch the automatically generated normals between vertex and point, as well as set the cusping angle for vertex normals.

http://www.sidefx.com/docs/houdini/ref/windows/displayopts_3d#normals [sidefx.com]

Edit:
keep in mind that this is simply the viewport display. Mantra provides similar control over automatically-generated vertex normals, but with more granular control over which objects have what type of normals generated. Fortunately, I believe the default is the same for both. Some mesh types are not subject to auto-cusping, such as non-polygonal types and polysoup primitives with fused vertices.

Yeah..but to me the question was why the difference between the two.

Both have the display tick options for all three normals - point, prim, vertex.

But looking a bit more, with your tip about cusp angles…In the geometry tab (H16) under normals section there is a choice between which normal to auto-generate ( point or vertex ). Setting it to point gives the same display behaviour as H15.5

The normals section under geometry tab in H16 isn't in H15.5.

So I guesss the default in H15.5 was to auto-generate point-normals. And opening a new H16 file I see auto-generate is set to default for vertex.

Looks like this is the reason the OP is seeing a difference for the same Box.

The reason to auto generate vertex normals (with cusp angle) is so that things like boxes look like boxes.

Anyone know if it is possible to set defaults to revert to the pre-16 behavior? Saving defaults from a scene viewer only affects that desktop, and doesn't affect mantra renders. Ideally there is some env var that can be set.

If you click on Save as defaults in the Display Options, I thought that saved to your ~/houdiniX.Y? I think this only determines the default for new scenes though.

edward
If you click on Save as defaults in the Display Options, I thought that saved to your ~/houdiniX.Y? I think this only determines the default for new scenes though.

I don't like saving the display options as defaults, because it saves every setting. I don't want color correction or background images to be saved into the defaults. Because that's only for the viewport preference, how do I go about altering a render property default?

You can save as default, then edit ~/houdini16.0/display.prefs and delete the prefs you don't want (it's a text file). And always do save as default from a fresh session. Don't know about mantra properties though.

twod
You can save as default, then edit ~/houdini16.0/display.prefs and delete the prefs you don't want (it's a text file). And always do save as default from a fresh session. Don't know about mantra properties though.

Thanks, I'll consider that.