DUCS in Shape vs Bricscad

Tom Foster

In https://blog.bricsys.com/shape-basics-create-roof/ at 0.09sec, what exactly is happening here?

In Shape, after starting the Shape (Polysolid/Linear Solid) command, "Align the drawing plane to the wall face by pressing Shift while hovering over the wall face" (the face highlights pale blue with the hover and then goes darker blue with Shift).

This looks like DUCS - Dynamic UCS - in BricsCAD, as described at end of User Coordinate Systems in v18 Help.

In the Shape video it's described as "Align the drawing plane to the wall face" which sounds like a planar version of linear Snap Track Lock - and sometimes in Shape it does act that way -
lock the plane and then drawing points placed away from that plane get projected to the perp point on that plane - invaluable.
It works sometimes in Shape but not reliably.

But doesn't work ever in 3D Bricscad. A drawing point placed away from the locked UCS's XY plane stays there, tho is subject to the UCS for orientation etc.

Is there some setting to make it work like in Shape, as described above? It's an invaluable feature, when it works, in Shape.

Roy Klein Gebbinck

Look at the OSOPTIONS and OSNAPZ variables.

Tom Foster

Brilliant!

But leads to next question - OSNAPZ refers to ELEVATION system variable - what might that be?
Searching ELEVATION in Settings just leads to OSNAPZ - doesn't produce an entry that describes ELEVATION at bottom.
On command line it's a 0 or 1 - but what does it do?

I see your wonderful public-service document https://www.cadconcepts.co.nz/assets/Blog/2012-02-Feb/Bricscad-V12-Variables.pdf but that doesn't explain what ELEVATION does.
BTW, do you have a v18 (v19 shortly) version?

Michael Mayer

I very recently heard of DUCS SHIFT Lock for the first time
and find it extremely cool.
(I currently have no access to my Bricscad Settings)
So I tried a few times (I think in Bricscad) and it worked reliably
for me so far.

Just a general experience.
As long as I move or shake my cursor in any way,
Bricscad is somehow occupied mostly by reading the cursor,
and any STRG Switching, SHIFT Locking, Selection Highlight Refresh
or Key Inputs most times will fail.

Only when I really take my hand from the Mouse or lift my Pen
from Tablet to avoid any cursor movements - all single or double
Keyboard Entries will work as expected.
Maybe it is worth to take a closer look, if things aren't working
reliably, if they would work better when nailing down the
mouse cursor.

Tom Foster

@Michael Mayer said:
I very recently heard of DUCS SHIFT Lock for the first time
and find it extremely cool.

That was me I think! But then I found it become unreliable in Shape and non existent in Bricscad - till Roy provided the answer above.
More than cool - awesome!
But not always what i want to happen - so now I want a OSNAPZ toggle on the status bar at botom. Can't see how that's doable.

The other great thing is that Snap track lock is now also working reliably for me - why not before? I don't know.

Roy Klein Gebbinck

@Tom Foster: You are confusing me with @Jason Bourhill.
When I search for ELEVATION in the _Settings I find this description:
'Specifies the current elevation for new entities relative to the current UCS'

Tom Foster

Oh, sorry Roy and Jason

Strange - i get this (attached)

I find that ELEVATION 0 or 1 makes no difference?

"I want a OSNAPZ toggle on the status bar at botom. Can't see how that's doable" - I see it's an icon on the Entity snaps toolbar - that'll do.

Michael Mayer

I may be completely off of what your problem is but
I understand it as follows

Those 2 buttons on the left side of the Snap Icons Palette

-Z Lock
When ON you e.g. can't (?) draw a Box and Extrude the last (Z) value
downwards, like when you snap to something below.
When OFF, you can.

OSNAPZ
Basically it is like a lock for drawing on the XY Layer plane only.
E.g. when you draw a Rectangle in an ISO, like by snapping at the
top of a 5th floor Wall, it will still be drawn on the floor of your
1st Story.
While when OSNAPZ lock OFF, it would draw beginning at the top
of that 5th floor Wall's Z.

As it is Layer height - or UCS - (or even DUCS ?) it could be off of
global Z = 0.00.
Common usage for me would be to have OSNAPZ Lock activated
and set a custom Plane Elevation in Property Palette.
So I can snap anywhere but be sure to always draw at a special Z.
Like setting Plane to -15 cm temporarily, to draw structural Walls
directly on the Structural Slab, opposed to the Finish Floor at 0.00 m.
Or set the Plane to 2.40 m to draw a bunch of ceiling panels,
Set plane to 3.xx m when you want to work in your 2nd Floor etc.

Louis_Verdonck

Please notice that when OSNAPZ = ON, two entity snap markers display: the blue one indicates the actual snappoint, the red one indicates the point at the current Elevation.

Roy Klein Gebbinck

@Tom Foster: Are you using the Up and Down arrows to the right of the search field to find other 'hits'?

Tom Foster

Thanks for that Roy - now I can take back all my disatisfaction with Settings Search!
I get ELEVATION now.

Yes Louis, they make it clear.

Michael, I'll decipher that later on!