Dimensioning Very Large Objects

[Minnyman]

Hi all,

My question is regarding dimensioning very large objects (130 feet long). I have to dimension many small things on the larger one but I can only show a small section per D size sheet. I can only show about one fourth per page after changing scale so you can see the edges of the smaller objects. All of the smaller things are dimensioned in relation to each other because there is nothing on the larger one to dimension from as it is welded plate so there are no hard lines after being welded. Is there a way to transition from one sheet to the next so that the fab shop knows how each view relates to the one on the previous page. I was thinking of a line like a section line with letters on one sheet and the same line on the next sheet but am not sure if this is the correct way to do it.

Any tips would be appreciated.

Thanks
Minnyman

 

[MintJulep]

Match lines. You're on the right track.

There may be a specific line style for them in whatever standard you work to.

 

[ajack1]

In automotive design they work with car lines. Basically the whole car has a common datum reference point (the centre of the front axle) and a grid is drawn from this point in XY&Z at 100mm on the whole car but also on any individual parts.

That way every part can be referenced to any other part and it is also obvious where each part sits in the assembly. Most 3D CAD systems I am aware of have this facility; however there may be some that don’t.

 

[Belanger]

You can also use "break lines" which show removed material from the picture -- as if two ends of a long plank were compressed to be near each other. There are two common break lines: a wavy line, and an intermittent zig-zag line for longer spans.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

http://www.gdtseminars.com

 

[Minnyman]

Hey all,

Thanks for the info. I think I'll go with the match lines, I may look into the grid thing as well. Now to figure out if Solidworks has them or do I just need to make them myself. Also I tried the break views but that only works for the two ends as the small objects on the two middle sections have to be dimensioned off the other small objects and not the ends of the larger object. I plan on making 4 crop views, two end ones where I can make the first dimension from the ends and two middle sections with match lines. Actually now that I think of it I may need two of each crop view because after I put all the dimensions and then the weld symbols it may be a little confusing.

Oh one other thing, does the ASME Y14 just deal with GDT or does it deal with regular dimensioning as well? I was looking at the table of contents and it seems mostly to be about GDT.

Thanks for the help,
Minnyman

 

[Belanger]

Y14.5 deals with all dimensioning and tolerancing. But yes, most of the standard is devoted to GD&T because of its complexity. For the regular dimensioning stuff you can limit yourself to Chapters 1, 2, and some of 3.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

http://www.gdtseminars.com

 

[Jboggs]

"I tried the break views but that only works for the two ends"
I have created break views with multiple views of the same long part on several occasions. Just keep adding break lines where you want them. Sounds like the ideal solution for you. SW dimensions the views as if the breaks were not there so you're ok.

 

[Minnyman]

I have 150 1x3 and 2x4 inch parts to dimension that are spread across 130 feet. If they were spread out more evenly I think It would work but unfortunately they are not, so I would end up with a lot of break lines. Is that OK on a drawing view? On some I may have as many as 10 breaks. I did finish it using crop views and match lines and it looks OK, although I had to do multiple views of some of the same areas due to the density of parts and having to put weld symbols as well.

I'll do a view with the break lines to see how it looks.

Another question, do you have to do an aligned view if half of the area you are dimensioning is angled slightly, or can I pull in the view already normal to the angled surface. The reason I ask is because the aligned view is at an angle on the sheet, but if I bring it in already normal then it will be horizontal with the sheet or can you go both ways?

Thanks for the help,

Minnyman