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Query on Plant Layout drawings

Query on Plant Layout drawings

Query on Plant Layout drawings

(OP)
Hi folks,
I have a small query on creating Plant layout drawings in AutoCAD. I just wanted to know how to start and proceed big drawings( in metres) such as Plant Layouts.My doubt is on setting the drawing limits, Plot scale (for plotting the drawing on an A3 sheet),if the drawing is given with a scale of 1:30 ,should I use the scale command.how do I manage the annotations and dimensions sizes for such drawings in print?

Can you please detail me on proceeding for such a drawing from scratch to Print?

Thanks in Advance.

RE: Query on Plant Layout drawings

Drawing extents/limits isn't something I worry about too much... I normally include property boundary. I use a standard set of drawing layers... similar to the AIA, but, with a heavier emphasis on structural items. If you have a survey, then you can include it on a layer. I make sure that the surveyor provides AutoCAD compatible drawings of his survey with the data on it. I may have 2 or 3 survey layers, all with different text heights for different scales. This solves the problem of having different text heights for the survey information if used for different drawing scales. . I then establish a base point on plan. This can be an actual benchmark, a property stake, a building corner, or whatever (something that will not move), and establish all work locations relative to this. I will define a new building corners as an x, y, and z offset from this 'benchmark'. I then go ahead and start my new structure with a building outline on the plan and the actual building drawings off the plan area. I use paperspace to set things out for plotting. Real CAD people may do differently; I've never taken any formal CAD courses... strictly from Omura's Mastering AutoCAD from several decades back.

I don't know if there is a current edition, but, the book was fabulous and an incredible help.

Dik

RE: Query on Plant Layout drawings

(OP)
Hi Dik,
Thanks a lot for your details.Highly appreciate your response.
But I just wanted to know how to start and proceed on a A0 size drawing in AUTOCAD?
What are the steps involved in it as it is a bigger size?

RE: Query on Plant Layout drawings

No difference... just use a bigger/smaller scale to suit... I have standard defpoint drawing sizes with 1/2" border... I put them on the model and increase them by the scale factor ... pretty quickly zero's in on the maximum scale you can use. A real CAD operator may have a better method than mine...

Dik

RE: Query on Plant Layout drawings

Was just thinking (an occasional occurrence) if you can use an A1 rather than an A0, you can shrink the drawing to an 11x17 size... I find the text on A0 to be too small when shrunk. it's a lot easier to work with in the field.

No one likes to work with large sheets.

Dik

RE: Query on Plant Layout drawings

(OP)
Thanks a lot Dk. Hope I can try these tips.

RE: Query on Plant Layout drawings

Glad to help... I was hoping that some one more knowledge would 'jump in'... there may be more professional ways of dealing with this.

Dik

RE: Query on Plant Layout drawings

I learned AutoCAD by reading 'Inside AutoCAD' from front to back, and working _all_ of the examples.
That was when version 10 (for DOS) was current.
I have no idea what text might be most useful now, but I do suggest working through one such guide instead of wandering aimlessly.
At least search YouTube for answers to your questions.


General suggestions:
Don't worry about drawing limits.
Aside from a numeric range limited to something like 16 decimal digits, the universe within AutoCAD has no serious limits. ... or units, really.
You can draw in Angstroms or in light years, it makes no real difference.
But you must draw full size, i.e., 1 unit on the model screen is one of whatever unit you choose.
Using the UNITS command or dialog early can be helpful with strange units like feet and inches.
Draw in Model Space only.
Dimension and annotate in Paper Space, mostly.

It helps to have a prototype drawing file to start from, hopefully something that's in the units you want, with a useful layer arrangement, and of an object about the overall size of what you want. Copy the file, or open and save under a different name, erase everything you don't need, and go. You can eventually make your own, but it's easier to start with one from someone who knows the software. There is a risk if you get a prototype from someone who is self-taught and does everything 'wrong' but in an internally consistent way, you will have difficulty producing what _you_ want.

Mike Halloran
Pembroke Pines, FL, USA

RE: Query on Plant Layout drawings

Thanks Mike... pretty much the same boat... I forced myself to sit down and do a chapter a night until I had completed the book. Maybe the site's policies about only engineers may restrict the comment. I was hoping that a real CAD operator that had been formally trained might be able to offer more technical information.

Quote (Mike)

But you must draw full size
Draw in Model Space only.
Dimension and annotate in Paper Space, mostly.

Missed those... and, drawing full size is critical and an essential habit to get into... A lot of my standard details are annotated with the drawing detail and scale factor of 16 and some with 12, but, often something else... I usually have my standard details in a defpoints 'box' with the dimscale, ltscale, text size, and last revision date outside the 'box'. I 'block' them into the model drawing and use different scale factors for the views in paperspace. There may be a proper way to do it... not aware of it. Just what I've done over the decades.

Should have added that honouring layer types is also critical and inserting blocks on Layer 0 is also important.

I usually have my borders and titleblocks as separate blocks with the titleblocks having attributes and insert these into paperspace; for a large project the common 'attributes' are filled in prior to inserting the block so I don't have to add them to the paperspace drawings. I also name the tabs in paperspace with the actual drawing name, eg., 17304S01, 17304S02, etc.

Dik

RE: Query on Plant Layout drawings

My comments pretty much fall in line with dik and MikeHalloran. However, I am also a self taught AutoCAD Certified Professional (ACP) with no formal training apart from OTJ experience.

We draw all drawings in model space but non-scaled drawings (i.e., P&IDs, PFDs, Isometrics) are dimensioned and annotated in model space and all scaled drawings are dimensioned and annotated (i.e., plot plans, orthos, etc.) in paper space. We plot everything to ANSI D (22x34) which allows us to print a true half scale to ANSI B (11x17) for convenience of handling. The only exception to that is Isometrics which are plotted ANSI B.

All annotation and dimensioning are done in paper space. Text heights are 0.125 (1/8") for general text, notes, and annotations and 0.1875 (3/16") for titles, labeling, and equipment tagging. Dimensions are left in inches up to 2'-0". Any dimension >/= 2'-0" is shown in feet-inch notation.

Every component is assigned a layer when drawn and all layers are given a discipline designator prefix (i.e., C for civil, P for piping, etc.) for ease of locating in the layer manager.

We don't really have a set scale for the drawings as the type of drawing can vary the scale. However, you can view the link below for common engineering scales.

https://www.engineeringtoolbox.com/scaling-bluepri...

Hope this helps,

DGrayPPD

RE: Query on Plant Layout drawings

(OP)
Hi Folks,
Delighted to receive such a detailed replies from you all. Wonderful!!

RE: Query on Plant Layout drawings

Typically use ANSI D, but, text is 5/64... some clients want 1/8". the smaller font is 'readable' when drawings are printed 11x17. I have a HP 350C D size plotter in the basement... my wife got upset and had me move it from the living room and due to difficulty, I hardly ever use it. Usually use ANSI D for drawing size... and plot to *.pdf which I can print on my laser printer...

Seems like everyone was 'self-taught'...

Dik

RE: Query on Plant Layout drawings

Go online for ACAD tutorials. From this forum you can not expect to learn ACAD correctly while it would take students several weeks to learn it correctly. I could teach you all the information that you are requesting but it would take several pages of instruction which is not the intent of this forum.

RE: Query on Plant Layout drawings

The resource provided by DIK is pretty a similar format that I used when I taught ACAD back about 17 years ago. It is a good program although it does lack a few features. Use it.

RE: Query on Plant Layout drawings

We had the same thoughts... tutorials... posted at 15 seconds apart...

Dik

RE: Query on Plant Layout drawings

(OP)
Hi Folks,
In continuation to this,i would like to clarify few points on units. When i start a drawing in metres (1 unit = 1 metres),what are the things I should consider when i take it to a print on an A3 paper which is in mm. Does it cause any problems? Need some light on this.

RE: Query on Plant Layout drawings

It shouldn't... draw your model space in units = m. Set your sheet and title block in paper space as full size in mm. Set your viewports and set the model space scale to suit... it's very easy and fast. Hopefully you've gone through a couple of tutorials on paperspace. There was one tutorial I encountered that was excellent, and, I cannot locate it. Good

Dik

RE: Query on Plant Layout drawings

(OP)
Excellent!Thank you Dik.May be I should try these tips straight away.

RE: Query on Plant Layout drawings

I'm a big supporter of 'tinkering' and I think too few people do it these days... once you have a working drawing in both model and paperspace, it's a matter of changing a few things, moving a few things around, etc. just to become familiar with the cad program.

As a caution, it is possible to change the original model from paperspace, so be careful and 'lock' your viewports.

Dik

RE: Query on Plant Layout drawings

(OP)
Hi folks,
In continuation to this, I just want to clearly understand the concept of defining limits in an AutoCAD drawing.
For example, I can draw any drawing of any size (which is in metres or MM) approximately and proportionally without any specific dimensions and I can take a print on any size. What is the significance of setting the drawing limits for a drawing? How does it affect my drawing sizes and Print sizes? Need more clarity on this topic please.

RE: Query on Plant Layout drawings

I don't use limits at all. I draw full-size, full-scale in model space. I draw in inches, decimals or millimeters depending on how the actual construction is measured. Only parts go in model space, everything else in paper space. I scale viewports in paperspace either for clarity or to specific scales if people will scale off the drawing in the field.

RE: Query on Plant Layout drawings

(OP)
Hi IFRS,
Thanks a lot for your insights.I expect few more replies from our experts on this.

RE: Query on Plant Layout drawings

A note about scales not mentioned yet.
After you've settled on a paper size you are going to use and have your border setup, you then know the biggest viewport you can fit on a sheet. Ideally, you will want to use the biggest viewport you can leaving room for notes, legends, keyplan, etc.

Once you have your basic viewport set, you can set your scale. The scale of your viewport(s) should be the smallest possible to fit your plan within the confines of the viewport AND be a standard scale. If you find that the drawing is illegible when showing the limits of the plant consider breaking things up and show only a portion of the plant on a sheet. This doesn't mean breaking up the model space drawing, just show a portion of the model in each viewport on each sheet. There is no limit to the number of sheets you can use, use as many as is necessary, a few years back I had a project that used about 20 sheets. The important thing is that the plans are legible. (And the same scale from sheet to sheet.)

A "standard" scale being a scale found on your desktop scale and fall into one of two types architectural and engineering. In my work, I use almost exclusively Architectural scales (1/8=1'-0", 1/4"=1'-0", 3/16"=1'-0", etc) so am not that familiar with all the standard engineering scales although 1:30 does look like one.

RE: Query on Plant Layout drawings

Standard scales are only needed if a user will use paper copies of the drawing and wants to measure things on the paper. This assumes of course that I know the printer they are using, their paper size and available print area, and that they are not using a copier or printer that arbitrarily prints to fit or copies not quite 1 to 1. Half of my clients never do this - they are machine or fabrication shops, their drawings are always B size 11 x 17 with viewports scaled for clarity, I zoom in to details without the need to restrict myself to standard scales.

RE: Query on Plant Layout drawings

(OP)
Hi,
Thanks a lot for your insights IFR and Dbill74 .very useful information. What I understand is that the plot scale of 1:1 is not mandatory in all cases and that the drawing just needs to be legible enough.
So can we conclude that the drawing limits we set is used for setting the sheet size on which we would be plotting?

RE: Query on Plant Layout drawings

(OP)
Hi folks,
Any conclusions or inferences to this topic "Limits"?

RE: Query on Plant Layout drawings

I suggest that limits are an artifact of a time long ago when they served a purpose, and no Marketeer will ever remove a 'feature' from a product, even if no one needs it or even knows what it does or once did.

Mike Halloran
Pembroke Pines, FL, USA

RE: Query on Plant Layout drawings

IMHO the only value of setting limits is that AutoCAD prevents you from putting objects outside the drawing limits. This can save you from from oopsies down the road.

RE: Query on Plant Layout drawings

(OP)
Hi,
Nice to see your replies.I just want to understand the concept of units in AUTOCAD. If I set the insertion units to metres,then is it that I am setting my current drawing units to metres.
How does the plotter or print recognise my units if it is in metres or MM.

RE: Query on Plant Layout drawings

The plotter has no clue what the units are. Autocad creates a plot file of whatever you tell it to - Display, Limits or Window - and streams that to the printer. You decide what objects are included in the print job, the paper size, how they are scaled and any X or Y offset etc.

RE: Query on Plant Layout drawings

(OP)
Hi IFRs,
Thanks for your prompt response. Say if i draw a line for 5metres and plot it on an A3 sheet with a plot scale of 1:1,then what is the result I can expect on the plot?
By the way could you please clarify me on the concept of units in AutoCAD?

RE: Query on Plant Layout drawings

Hi Sudharkarn,
There are multiple places you encounter so-called "units" in AutoCAD, so I'll discuss the three that come to mind:

The command line UNITS defines the number of decimal places that will be shown on all coordinate readings, measurements, and distance calculations.

The dimension style dialog box can also define a parameter that will convert the measured values in the dimension lines. This parameter can be anything you specify, but by default will probably multiply the basic measurement by "25.4". It can easily be changed to "0.3048" or something else that is useful.

The printer dialog shows the scaling units to be used when printing the drawing, which is the ratio of the selected area to plot to the area available to plot on the paper.

Note that NONE of my descriptions have involved the terms "meters" or "inches" or "millimeters" or any term of measurement whatsoever. AutoCAD does not know what they are!
I repeat, there are NO UNITS OF MEASUREMENT in AutoCAD. All appearance of using units, such as the dimension styles, is just printing of letters such as "mm" after a result - not due to AutoCAD having any knowledge that the measurement is intended to be millimeters. Same goes for dimension expressions of feet/inches with the '/" characters - it all just a bunch of factors and multiples to be calculated, not a reflection that one drawing is "imperial" and another is "metric".

The closest AutoCAD gets to using actual real-world measurement units is the printer dialog - but even there it's just arbitrary. I had a lot of school friends who would constantly over-think the whole thing.

STF

RE: Query on Plant Layout drawings

sudharkarn - Here is an example. In a new drawing, in Model Space, draw a line from 0,0 to 5,0. In your mind it is 5 meters long. Autocad only knows it goes from 0,0 to 5,0. Autocad does not know if it is 5 angstroms or 5 light years long, nor does it really matter. Now let's plot it. In the plot dialog, choose "Center the Plot" for the plot offset and "Extents" for what to plot. Autocad will print everything in Model Space centered on the paper. Now choose a paper size, for now choose ANSI B. Now look at the plot scale options. If you choose "Fit to Paper" it will scale the 5 unit line to fit on the paper. The plot will be a straight line across the paper, starting and stopping at the paper margins. If you choose 1 inch = 1 unit it will try to print a 5 unit long line on ANSI B size paper which will be 5 inches long and will not use all the paper. If you choose 1 mm = 1 unit your 5 unit long line will print 5 mm long and again will fit. If you choose 1,000 mm = 1 inch you will see a small portion of the line because your line is 5 units long, each unit is being plotted as a meter and your paper is much smaller than a meter. Try this a few times with a more useful drawing.

RE: Query on Plant Layout drawings

(OP)
Hi folks,
Excellent!Now I feel enlightened and now it's time for the practical experiment.Thanks a ton your detailed insights.

RE: Query on Plant Layout drawings

I often add a scale 'bar' to drawings. This shows the 'length' of a foot or unit. When drawings are plotted to 11x17, you can get an idea of what a foot or 10' looks like on the plan.

Dik

RE: Query on Plant Layout drawings

dik is absolutely on point. I do the same thing, even if the drawing is meant to be scaled off of, just in case it is printed on a different device or different size paper.

RE: Query on Plant Layout drawings

(OP)
Hi Folks,
Brilliant!Very much helpful ideas that will make any one's day.

RE: Query on Plant Layout drawings

I used to work in a fancy sheet metal shop, where we made our own tubing because the best material was available only in sheet form. Because of the nature of the product, we then faced the task of fabricating elbows and tees with branches at very odd angles, for which purpose we produced full size templates for cutting blanks or trimming tubes.

After scrapping too many thousand dollar sheets of Six-Em-Oh, I changed our procedures so that each template drawing file included a dimension between two targets, that was to be measured on the actual template, and initialed, before the template went into the job folder for fabrication.

The problem first came to my attention a long time ago, when I detected a three percent change in length in a diazo contact print vs. my carefully drawn vellum. That was long before CAD and printer/plotters, which allow an awful lot of opportunities to erroneously 'fit' an image element where you didn't intend to change it.

Mike Halloran
Pembroke Pines, FL, USA

RE: Query on Plant Layout drawings

Mike... I remember those 'good old days'... glad we got through them.

Dik

RE: Query on Plant Layout drawings

(OP)
Hi Folks,
Glad that the thread is getting inputs from all the corners.

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