Negative dimensions: why not?

Maybe newer SW can do this (newer than 2001Plus) but for some reason I
doubt it.

I want the ability to change any dimension to a negative number (or even
zero, for that matter).

Why is this useful? In my part I have a rectangular cut with a centerline
that is dimensioned to a plane in the middle of the part. If I want to
slide the cut to the other side of the center plane I have to edit the
sketch rather than just setting the dimension to -3. Likewise if I need to
locate the cut in the center I again have to edit the sketch.

Yes, I could change the dimensioning scheme to reference one of the outside
edges rather than the center plane but then I may have to sacrifice other
things (like design intent).

It just seems like it should be such a simple thing to add this.

Or maybe my ProE background has twisted me.

Joel Moore

 

You know what? This appears to be a tired issue. After searching Google
(after posting, of course) I realize now this has been debated to death.
SW is obviously never going to enable this ability.

Never mind.

Joel Moore

 

Hi Joel,

I also find it strange that we can flip the sense of things when
mating and using offset from surface, but cannot do this with sketche
dimensions.

Along the same lines, is seem absolutely insane to not be using signed
coordintes with ordinate dimensions. I have had many cases when my
zero point (ok not always the ouside of the block) made a hole that
was .0027" from zero? Buy which way you ask? I don't know, lets just
guess, the perforator can flex a bit and hopefully not break . . .

Renee Descartes must be rally pissed that these folks have used only
HALF of his grand co-ordinte system by presuming that nobody would
ever need to use a negative value. But hey, you cah always manually
add a negative in front of the dimension, but lets hope you don't
change anything to make it move across the line . . .

Enjoy -

I agree

SMA

 

René is a "he" ;=)))

 

Joel,

I'm with you, this would be such a nice addition to SWX. I have been
begging for it since 98+ to no avail. I used to run ProE and could
give dimensions negative values. (ProE handled them kind of strangely)
But one situation I run into a lot is angular values. What a pain it
is to have to edit the mate to get something to move from above
horizontal to below.

Dear Solidworks,
Instead of fancy schmancy new features that seem marginally useful
(like shadows and skins for the feature manager) and concentrate on
something boring but usefull like negative values.

Just venting a little

Bryan

 

(Sean-Michael Adams) wrote in

Actually, it's only 1/8 (in 3D space).

 

And it's really strange that you HAVE to use negative dimensions in section
views!

Unfortunately, it seems that the folks at SolidWorks have their heads so far
up their asses on negative dimensions in any other place that it will never
get changed. What a waste!

Jerry Steiger
Tripod Data Systems

 

Now you've done it. Your VAR has just out you on their 'black list'
and SolidWorks has put your email address on a filter that sends them
right to the trashcan.

SSSSSSSHHHHHHHHHH.
lol!

 

They don't provide for opposite directions everywhere and they don't do it
in a consistent fashion where they do.

As a very simple example, suppose you are putting a hole in a plate and you
want it 3 inches from the center line. You put a circle in a sketch and
dimension it from a center line. Now you decide to put the hole on the other
side. It would be nice to just enter a minus sign in front of the 3, but you
can't do that. Suppose you have used that hole location dimension in your
drawing. If you delete the dimension, you have to reinsert it in your
drawing. So you have to set it to driven, drag it to the other side, then
redimension it at 3 inches. Wouldn't it be a lot easier if you could put in
negative numbers?

Jerry Steiger

 

Does anyone remember that there was a version of SW that allowed you to
change the direction of dimensions? Ever wonder why the "Modify" box is
long enough to have an extra button on it? I think it was removed in 97+
because it didn't work right. whatever.

If you use "Override dims on drag", you can get dimensions to go a
different direction. It's not a good solution, but it might be better than
deleting and recreating dimensions.

matt.

 

matt points out <<If you use "Override dims on drag", you can get dimensions
to go a
different direction. >>

I agree this is not ideal, but in the absence of ability to use negative
numbers, it's damn useful.
So useful that I find it irritating that the command is so inaccessible and
there are no status indicators.
My user group voted for and submitted an ER for a toolbar, perhaps living in
the status bar at the bottom of the screen, with different coloured traffic
lights for the different sketch settings, identified by tooltips, and with
the ability to toggle them on and off by double clicking on them.

Given that some of these settings are powerful and can screw with your
sketch, you don't want to toggle them on accidentally.
I hit on the short term solution (which I use for "Override dims on drag",)
of assigning a multiple key shortcut (I use Ctrl-Alt-O), on the principle
that I am never going to accidentally invoke something which requires either
both hands or the technique of a concert pianist.
It is testimony to how much I use this that I find I can always recall the
shortcut.

The way I use it for reversing the sense of dimensions is to clear my mind
of distractions, invoke the shortcut, drag the dimensions across, reinvoke
the shortcut IMMEDIATELY to cancel it (even if the phone starts ringing),
then edit the dimensions. If a target dimension is critical, I might type
the desired figure into the text comment area of that dimension's dialog box
before I make the change.

If there's only one dimension to change, it may be more practical to use the
"Driven"/"Driving" toggle recently added to the RMB context menu.

 

What do you expect from a program that only finally decided to make a
global XYZ coordinate axis triad an option to actually be seen now in
their *last* major upgrade? Never saw the (user's) need to use it
before?

I gave up before SW2003, but now is there only one point allowed per
X, Y, and Z coordinate point? It seems like I had problems with SW
trying to call the same point by 2 different X, Y, and Z
coordinates...or maybe that was more related to my next comment.

And what do you expect from a program that allows a separate origin
from part, to sketch, to sketch?

Frustrated Non-SW user at work (because of the hangups),
Ken

 

You're only talking about assembly mates and feature depths/heights. There
is no "opposite direction" concept for sketch dimensions.

If you haven't worked in another CAD system that supports this (i.e. ProE)
then I suppose you wouldn't understand the usefulness of it.

 

why can't or can we have negative values?<

This is an interesting question, and a puzzling one, for sure.

I don't know if D-cubed is the "hangnail" (nice tagline, Paul), or whether
neg dims simply hasn't worked its way close enough to the top of the master
ER list at Concord Mass.
In case anyone's interested, last time I checked on D-cubed's website, there
was only one other CAD developer who licenced as many D-cubed components as
SldWks, and it was for a CAD package that doesn't speak English- it looked
to be a proprietary spinoff from one of the Japanese automakers (Nissan,
from memory).

-- -- --
Personally, and this is probably entirely OT -- so please start a new thread
if you want to comment on the following-- I have always liked the
orientation of SldWks, right from the original '95 model, towards mechanism
simulation, and I have formed the view that their very heavy reliance on
D-cubed modules reflects and supports this.

(I don't mean to imply that SldWks 95 could simulate mechanisms in anything
remotely approaching the way we now can, but among its contemporary peers it
always showed a lot more potential in that direction, since largely
realised. From a very early date SW could model space linkages (ie linkages
which operate in 3D, ie balljointed), although my guess would be that most
users neither suspected nor could care less.
I particularly like the fact that this ability is part of the core package,
hence uses stuff which I grapple with on a daily basis. This inevitably
promotes intimacy (sometimes rather more than I would prefer) which in turn
pumps up the tyres on the workaround wagon.

It seems to have retained that lead in this area. Space Linkage design (or
verification) is one of the few tasks (organic surfaces are another) which
NEVER has me wishing I could wind the clock back to 2D drafting.

--(Gratuitous and contrived link back to original topic warning)--

If (and this is probably fanciful) the limitation were somehow intrinsic to
the architecture of D-cubed, AND if this implies that we are forced to
choose between bleeding edge mechanism simulation and negative dimensions in
sketches, I'd dive for the bleeding edge.

"It's better to burn out, that to fade away.......
They give you this, but you pay for that
And once you're gone, you can never come back
When you're out of the blue and into the black."