Things that drive me nuts ... 5

[jacek0841]

.
SW2005 SP4.0

- Open dwg, just for printing, PRINT , after that you want to close the file, without ANY changes - window pops up asking for saving changes ...... WHAT CHANGES ??? I haven't done ANYthing !!!

- Saving dwg with ONE sheet - window pops up saying Views on inactive sheets need updating ... bla ... bla ...

There in NO inactive sheets - there is only ONE sheet dammit !!!!

 

[ctopher]

I create all models as they get machined. If it's a turned (lathe) part, I use the right view. This make the side of the part the front, as if looking at it from the lathe. If the part has a feature for attaching a connector, the surface that sits on the machines table is the top view, the connector feature is toward the right. It's typical for cables to be shown connected from the right. All models have the origin in the middle, mounting surface. This makes showing CG easier to read and for mating in assy's. For lathed parts, origin on center plane either at end or middle.

Chris
Systems Analyst, I.S.
SolidWorks/PDMWorks 05
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

 

[wgchere]

Long before cad packages were developed the x-y-z orientation was fixed with the z-axis being vertical. This is the essence of the "right-hand rule" I learned in physics.

AutoCAD started and is still mainly an architectural/Civil engineering package. Yes, the z-axis comes out of the screen, but the screen is looking down. AutoCAD's native view point is called a plan view. What is a plan view? It is a view of a plot of ground from the air. The x-y axes are on the ground, the z-axis is gravity. Cadkey started as a wire frame 3D package. The z-axis is vertical. Pro-e has the z-axis vertical (at least PTmodeler did). Look at your old drafting texts and I'll wager you'll find that, when the term is used, z-axis is up/down.

CBL, you may have never heard about difficulties with CAM programs translating a sideways part (milling and workstation setups). I had no idea until one of the CAM programmers made a casual comment and we found out we were causing a bit of lost time from our orientation. They had never said anything about it because they thought their practices were causing the problem! We paid attention to orientation and the problems practically disappeared.

Now, I’m not talking about drawings here, I’m talking about the 3D orientation of model space. On a drawing each view can have an x-y orientation, which is dependant on the horizontal/vertical of the paper, not the part orientation.

 

[SolidCreative]

Anyone ever want to flip a dimension, or set it to zero!!

I dimension holes and sketches to the center line, orgin of the part. But solidworks wont let me put in a negitive value, or set my dimension to zero when moving into a new quadrent or when the hole or sketch becomes aligned with the center axis!!

I am forced to delete the dimension, move the hole to opposite side of axis and redemension.

 

[dgowans]

SolidCreative,

When faced with this in the past, I have made the dimension in question a driven dimension and then dragged the sketch entity to the other side of center. Make the dimension a driving dimension, modify the value to what you want - DONE!!!!

A complex constraint network might force you to do this to several dimensions, but this should work for most sketches.

 

[BiPolarMoment]

I'd much rather solidworks be "smarter" about that particular issue, especially if for instance, you wanted an equation to be able to drive the feature "negative" without having to dimension from a different point to ensure it's always positive--sure you can work around it, but why should you have to?

 

[ctopher]

There shouldn't be a neg or 0 dim. Why would you want to? It doesn't benefit anyone, just creates confusion. Place your feature approx where you want it and dim it.
Also, always dim your part they way you want the part made. I see parts dim one way and dwgs dim another. This makes the CAM people make a part one way and inspection use the dim's from the dwg another way, creates bad parts.
Just a FYI.

Chris
Systems Analyst, I.S.
SolidWorks Pro 06/PDMWorks 06
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

 

[SolidCreative]

Thanks for the FYI, but I and everyone in my company do our best to dimension patterns to the center line. When a hole pattern cross the origin into a different quadrant, you must delete, reposition the pattern, and reinsert the dimension. If the pattern moves to be along the axis of the origin you have to delete the dimension and add a vertical mate. By allowing zero and negative mates this problem would not occur. FYI. Maby they could make a simple version for anyone this confuses.

 

[SolidCreative]

correction. By allowing zero and negative dimensions, not mates.

 

[ctopher]

If it was zero, it wouldn't be a dim. Curious, does the shop measure from the CL to make the holes on all your parts?

Chris
Systems Analyst, I.S.
SolidWorks Pro 06/PDMWorks 06
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

 

[CorBlimeyLimey]

SolidCreative ... this would be a perfect example for using planes to locate the hole centres. Offset planes could be placed wherever needed with the hole centres being made coincident with them. Then, when a hole needs to "flip" into another quadrant, all that is required is to reverse the offset direction.


Helpful SW websites FAQ559-520
How to get answers to your SW questions FAQ559-1091

 

[ewh]

UG allows sketch dimensions of zero to constrain geometry, as well as negative numbers (not recommended) for situations such as SolidCreative mentions, so it is not out of the realm of CAD.

 

[BiPolarMoment]

I apologize, ctopher, but I was thinking like I was still using pro-e. The best way I could find to get an axial sectioned helical cut would be to drive the angle with an equation using a variable section sweep over the length (trajpar function) e.g:

http://blennopho.be/helicalgear.jpg

Excuse the fake involute and silly render, it was my first model back then.

In those cases, there was no easy button to reverse the direction of the helix like in SW since it was all originally dimensioned as an angle (though you could use an equation to derive it from pitch/length if necessary). It was a modeling issue at the time, not a drawing one.

I sure hope Pro-E has gotten better, because simple stuff like that shouldn't be so complicated--normal helical sweeps weren't much better.

 

[ongybill]

I have to disagree that negative dimensions don't benefit anyone. Positive and Negative coordinate systems are often used in engineering; and are a staple in mathematics.

Over the years I've designed several irregular motor mounts ect., where the most sensible way to dimension it was from the center of the circular pocket used to locate the motor. Usually the motor holes can be dimensioned as a bolt hole center, but gearboxes often have rectangular or irregular bolt hole patterns. And often there are a myriad of other mounting holes that don't follow any set pattern. The only important thing is that they are precisely located from the motor center (Say +/- .003" tolerance). While the outside plate dimensions aren't very important (+/- .125" tolerance).

From a CNC machining standpoint it's child's play to program this part using positive and negative XY coordinates, particularly if the hole locations are listed in a spreadsheet format. The negative X/Y values immeadiately identify where the hole is located. Using all positive dimensions doesn't identify which quadrant the hole is in, and make it much easier to make costly mistakes.

I find this a real weakness of SW.

 

[ctopher]

I was thinking of the model itself, not the dwg.

Chris
Systems Analyst, I.S.
SolidWorks Pro 06/PDMWorks 06
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

 

[ongybill]

I was thinking of the model itself, not the dwg.

Either way. I've converted many dwgs from paper dwgs to solid models. It's much easier & faster in a program that simply allows you to enter hole centers using a coordinate system.

I just don't get the reason for the artifical limitation SW imposes here.

Same with dimensioning to zero. I've had several times I've wanted to lock a center point to a particular point on a sketch (particullarly when there are several configurations of a part). I want it 0" from that point, but I can't do it. Zero isn't allowed. I can generally figure out a convoluted way around this, but simply dimensioning it at 0" from the desired point would be 100 times better and much more straightforward. It will allow you to dimension it at 0.0001" away. Which you'd think would be sufficent, but 100,000th is far enough off it'll mess up concentric mates. Really wish they'd fix this one. Zero was invented thousands of years ago, wish someone would clue SW in.<G>

Best workaround I've found is to draw a point .1"X & .1"Y from where I really want it, dimensioning the unnecessary point off the useful point, and then the desired point off the unnecessary point. Not really complaining; it's those dozens of extra steps that make SW such a joy to use.<G>

 

[ctopher]

I gues I'm not seeing it. Can you show a pic of where a zero dim is needed?

Chris
Systems Analyst, I.S.
SolidWorks Pro 06/PDMWorks 06
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

 

[mncad]

ctopher,

I don't have a picture but we use 0 as a dimension also. We build indexable cutting tools and sometimes the cutting edge is on centerline of the cutter, sometimes it is above or below. I would like to be able to dimension the edge on center at 0 instead of just using a note saying it is on center. That way if the design changes and the cutting edge goes above or below centerline the 0 dimension could update automatically, don't have to worry about manually updating a note. It may not be ANSI or correct to the drawing codes, but the people in our shop understand it and it works well for us.

mncad

 

[smcadman]

The only time I have seen "0" dimensions used is on ordinate dimensions and bolt hole circle patterns. Also, SW allows negative numbers on hole tables. The use of zero dims may depend on your field of work.

Flores
SW06 SP4.1

 

[ongybill]

I gues I'm not seeing it. Can you show a pic of where a zero dim is needed?

Who's talking NEEDED. I'm talking EASE OF USE. SW will draw anything I want it to. But, IF and ONLY IF I draw it in EXACTLY the manner SW likes. This just seems like a meaningless hoop to jump through.

Usually this comes up when I need to go back and move something so it lines up with something else. A zero dimension would be the Simpliest, Fastest, and Easiest way to do this, but it's NOT ALLOWED.

A dimension of ZERO is just as valid as a dimension of any other #. It precisely locates something in relation to something else as well and as accurately as any other dimension does.

Perhaps you can't see a need for it. But, can you explain to me WHY it's NOT ALLOWED? What terrible things would happen if ZERO dimensions were allowed? Personally, I can't think of a single problem it'd cause (I'd be interested if someone can think of some). On the other hand, I can think of many instances where it'd be useful. It's also something I've used hundreds of times with other software with ZERO problems.

 

[ewh]

Are we discussing zero dimensions on a drawing, or in a sketch? I am one of those that sees no need for them on drawings. It just confuses the issue to have to dimension features on a centerline as being zero from that centerline.