It's winter here in NZ and contrary to what the nice tourist posters tell visually, I can confirm that Auckland in the winter is pretty miserable, with rain most days.
Consequently, I'm frequently telling myself a warm office is a good place to be!
Sometimes I believe me, but I would rather be curled up at home with a good book.
Recently at work I have been asked to do a drawing showing how the hot water piping is run throughout the plant. In a previous go at this, I had a 3D model, which I exploded into lines so that everything was "X-Ray vision".
This did not work out that well as you ended up with a forest of lines which had to be grey to fade into the background. So the latest attempt involved getting a 3D model of the plant and
running my pipes around that. The buildings are just "shells" to minimise clutter, and I xref in the bits of plant that I have drawn previously.
Still not the ideal solution, and just seems a struggle.
The plant is here: http://www.chelsea.co.nz/content/about-chelsea/default.aspx
I'm starting to wonder if my approach is correct.
Tuesday, July 6, 2010
Saturday, June 12, 2010
Want to draw wooden windows then?
On a previous blog,
I gabbed on about a sorry saga of making a lisp routine to draw doors and windows.
It has now been posted on my website, if such a beastie is your thing.
Saturday, June 5, 2010
Autocad as a desk-top publisher
I recently was asked to do a site layout, just a general map showing where the main buildings were. This was to be a 3D job. As I already had a 3d model, it was relatively simple to chuck a few materials on and render it.
Then the thorny question arose: How to put annotations on a jpg? The silly answer is of course use Microsoft Paint. Silly, because it came out looking like crap!
Once upon a time, I had my own computer at work and my own copy of Corel Photopaint, which would have done the job. Unfortunately, I now work on the firm's supplied computer and the preventers of information technology dept have it so you must ask for such software to be installed. It can be done, but the thought of all the forms and fighting bureaucracy put me right off.
Then the penny dropped: why not use Autocad? Just drop the jpg into modelspace, put the annotations in paperspace-easy.
Then the thorny question arose: How to put annotations on a jpg? The silly answer is of course use Microsoft Paint. Silly, because it came out looking like crap!
Once upon a time, I had my own computer at work and my own copy of Corel Photopaint, which would have done the job. Unfortunately, I now work on the firm's supplied computer and the preventers of information technology dept have it so you must ask for such software to be installed. It can be done, but the thought of all the forms and fighting bureaucracy put me right off.
Then the penny dropped: why not use Autocad? Just drop the jpg into modelspace, put the annotations in paperspace-easy.
Thursday, May 6, 2010
A CAD Standard
Here it is - it may not be perfect, but anything is better than nothing!
Unfortunately in the process of getting it here all the formatting is gone....but the info remains!
Introduction
This procedure provides a basis for to produce drawings to NZS5901 (1987), ENGINEERING DRAWING PRACTICE IN NEW ZEALAND using AutoCAD.
This standard also lists the changes to the AutoCAD configuration, and forms a basis for layers, text styles and system variables as required.
All drawing numbers to have prefixes as follows:
L=Layouts
P=PI & IDs
E=Electrical
S=Process Flow Diagrams
Paper and Model Space
Place entities as follows:
Paper Space
Title Block at 1:1 Scale
Annotation Text/Dimensions for 3D Views
Parts Lists
Model Space
Object outlines
Dimensions
Annotation Text for 2D views
Sheet Sizes
Drawings to be on A1 Title Block, and usually this is printed on at A3. This means the 3mm high normal text comes out at 1.5mm printed.
Units
All units in millimetres
Plotted Line Width
ALWAYS AN ENTITIES COLOUR SHOULD BE "BYLAYER". Hence whatever layer an entity is on controls its plotted line width
Plotted widths to be 0.05mm, 0.2mm, 0.45mm
The only exception is dimension lines, these are forced to white for the lines only.
Plotting and Scale of Entities
Plot scale is controlled by setting the zoom factor while in Model Space, for instance if the drawing is to be 1:5 scale, you would go to paper space, then enter Model Space by double clicking in a viewport, then type "ZOOM" "1/5xp". Then double click outside the viewport anywhere in paper space to get out of the viewport.
All entities to be drawn in Model Space to be full size, i.e. 1mm=1mm
Limits
These are set to an A1 sheet in the prototype drawing, and are up to the individual user to set, as they may prefer. Remember a grid will not show up unless limits are set to cover the area.
Layers
For Mechanical Drawings:
These are the layers normally to be used, and come already loaded on the prototype drawing.
Layer Colour Colour No Line type Pen Width (mm) For
0 white 7 continuous 0.05 Blocks written to file*
CL magenta 6 centerx2 0.05 Centrelines
DIM red 1 continuous 0.2 Dimensions
HID magenta 6 hiddenx2 0.05 Hidden Lines
HVY cyan 4 continuous 0.45 Heavy Lines
LGT white 7 continuous 0.05 Light Lines
MED yellow 2 continuous 0.2 Medium Lines
PH grey 253 phantomx2 0.2 Phantom lines
For Process and Instrumentation Diagrams (P&IDs):
Layer Colour Colour No
Valves yellow 2
Product red 1
CIP magenta 6
Equipment Major white 7
Equipment Minor grey 252
Instruments white 7
Instruments-Control white 7
Text white 7
Services-Gas light blue 140
Services-Chemicals Lt Green 83
Services-Liquids Dk Blue 145
Services-Compressed Air Lt purple 213
All linetypes are continuous for PIDs except for CIP, which is centerx2.
*NB When you write out a block to the library for other people to use,
put all of it on the 0 layer. In this instance you can make centrelines colour by name and
linetype not by layer. The advantage of this is that when someone brings it into a drawing, they
can put the block on a layer and it will show in that layer’s colours.
Plans and Elevations
These should always be in line with each other, ie if a vertical construction line is drawn through an item in the plan view, it should also go through the corresponding part on the elevation. This usually means that the view to the left of the plan view has the floorline running vertically up the page.
To make this view easier to work on just rotate your UCS by -90 degrees and issue the PLAN command. A lisp routine called RO90 will do this
automatically.
The commands are UCS, Z, -90, enter, Plan, enter.
Entity Creation Modes
Entity Mode
Colour Bylayer
Dimension line colour White
Dimension extension line colour White
Dimension Text Colour Bylayer
Dimension style "Standard"
Linetype Bylayer
Textstyle Standard
Dimension Variables, and System Variables
1. Ltscale will initially be set at 4 for the prototype drawing so that dashed lines show up.
2. Mirrtext should be set to 1,because you would never want mirrored text.
3. Dimscale will be set to 1 so that if you are starting a drawing at 1:1 you will not need to reset it.
Note that contrary to a lot of common practice, the units are set to 3 decimal places; not zero places as many people set them. The logic in this is that when machined items need 3 decimal places you do not need to reset the units. For normal whole dimensions, ACAD conveniently suppresses the trailing zeros-see the dimzin variable.
A noted drawback of this is that when you are dimensioning a hole in the middle of a piece of 75 wide flat, the dimension will come up as 37.5, giving rise to a tolerance of +/- 0.1mm which is clearly not desired. The fix of course is to enter the dimension manually at the prompt.
Linetypes
Use standard Autocad ACAD.LIN
Text
Heights and pen widths will be:
Entity Height Penwidth Colour
All normal text 3mm 0.3mm bylayer
Large text 4mm 0.5mm bylayer
Fonts
Use Arial
Scales
Category Recommended Scale
Enlargement scales 50:1 20:1 10:1
5:1 2:1
Full Size 1:1
Reduction scales 1:2 1:2.5
1:5 1:10
1:20 1:25
1:50 1:100
1:200 1:500
Item References
Shall use numbers, not letters. The text height will be 5mm high .The circle to be 10mm diameter.
Block Library
These are kept at
Various categories are used in this folder eg bearings\saeco
If drawing say a motor, have a dimensioned drawing showing 3 views,
plus separate plan, side and end views with no dimensions on.
Be verbose with filenames, eg do not put "150kw motor", put for instance:
"Electric Motor-Teco-315s-85r.-plan - 2D"
Issue of Drawings
Only the project engineer may issue drawings. A document transmittal (standard form) must go with the drawings and a copy kept in the job file. All drawings must be stamped as to their purpose e.g., construction, for information, for tender etc. The project engineer is responsible to see the drawings are checked in respect to design and dimensioning, before issuing any drawings. The project engineer must sign all drawings issued. A copy of any drawing issued is to be kept on a stick file specific to the job, while the job is in progress. Finalised drawings should be stored in the drawing cabinets.
Sections and Views
On any drawing sheet sections and views start at A and work forwards through the alphabet
Appendix
The following lisp routine sets up the layers for PIDs:
;Program written by Bill Le Couteur
;Auckland NZ
;Rev 0 date 18/8/97
;This program sets up layers
;the idea is that layer names are set ONLY
;by this routine...and this routine is run every time you open a drawing
;so if as a contractor you change employers, YOU ONLY
;HAVE TO CHANGE THIS ROUTINE
(defun c:laysetPID()
(setq the_layer (getvar "clayer"))
(setq layvalves "valves")
(setq layproduct "product")
(setq laycip "CIP")
(setq layequipmajor "Equipment Major")
(setq layequipminor "Equipment Minor")
(setq layinstruments "Instruments")
(setq layinstrumentscontrol "Instruments-Control")
(setq laytext "Text")
(setq layservicesgas "Services-Gas")
(setq layserviceschem "Services-Chemicals")
(setq layservicesliquids "Services-Liquids")
(setq layservicescair "Services-Compressed Air")
(command "-layer"
"m" layvalves "c" "33" layvalves
"m" layproduct "c" "1" layproduct
"m" laycip "c" "6" laycip
"m" layequipmajor "c" "7" layequipmajor
"m" layequipminor "c" "252" layequipminor
"m" layinstruments "c" "7" layinstruments
"m" layinstrumentscontrol "c" "7" layinstrumentscontrol
"m" laytext "c" "7" laytext
"m" layservicesgas "c" "130" layservicesgas
"m" layserviceschem "c" "111" layserviceschem
"m" layservicesliquids "c" "145" layservicesliquids
"m" layservicescair "c" "213" layservicescair
"m" "TEXT" "c" "120" "TEXT"
"s" the_layer "")
(command "-laYER" "t" "*" "")
(command "-laYER" "unlock" "defpoints" "")
(setvar "blipmode" 0)
(setvar "ltscale" 4)
(command "regenall")
(setvar "CMDECHO" 1)
(princ)
)
Unfortunately in the process of getting it here all the formatting is gone....but the info remains!
Introduction
This procedure provides a basis for
This standard also lists the changes to the AutoCAD configuration, and forms a basis for layers, text styles and system variables as required.
All drawing numbers to have prefixes as follows:
L=Layouts
P=PI & IDs
E=Electrical
S=Process Flow Diagrams
Paper and Model Space
Place entities as follows:
Paper Space
Title Block at 1:1 Scale
Annotation Text/Dimensions for 3D Views
Parts Lists
Model Space
Object outlines
Dimensions
Annotation Text for 2D views
Sheet Sizes
Drawings to be on A1 Title Block, and usually this is printed on at A3. This means the 3mm high normal text comes out at 1.5mm printed.
Units
All units in millimetres
Plotted Line Width
ALWAYS AN ENTITIES COLOUR SHOULD BE "BYLAYER". Hence whatever layer an entity is on controls its plotted line width
Plotted widths to be 0.05mm, 0.2mm, 0.45mm
The only exception is dimension lines, these are forced to white for the lines only.
Plotting and Scale of Entities
Plot scale is controlled by setting the zoom factor while in Model Space, for instance if the drawing is to be 1:5 scale, you would go to paper space, then enter Model Space by double clicking in a viewport, then type "ZOOM" "1/5xp". Then double click outside the viewport anywhere in paper space to get out of the viewport.
All entities to be drawn in Model Space to be full size, i.e. 1mm=1mm
Limits
These are set to an A1 sheet in the prototype drawing, and are up to the individual user to set, as they may prefer. Remember a grid will not show up unless limits are set to cover the area.
Layers
For Mechanical Drawings:
These are the layers normally to be used, and come already loaded on the prototype drawing.
Layer Colour Colour No Line type Pen Width (mm) For
0 white 7 continuous 0.05 Blocks written to file*
CL magenta 6 centerx2 0.05 Centrelines
DIM red 1 continuous 0.2 Dimensions
HID magenta 6 hiddenx2 0.05 Hidden Lines
HVY cyan 4 continuous 0.45 Heavy Lines
LGT white 7 continuous 0.05 Light Lines
MED yellow 2 continuous 0.2 Medium Lines
PH grey 253 phantomx2 0.2 Phantom lines
For Process and Instrumentation Diagrams (P&IDs):
Layer Colour Colour No
Valves yellow 2
Product red 1
CIP magenta 6
Equipment Major white 7
Equipment Minor grey 252
Instruments white 7
Instruments-Control white 7
Text white 7
Services-Gas light blue 140
Services-Chemicals Lt Green 83
Services-Liquids Dk Blue 145
Services-Compressed Air Lt purple 213
All linetypes are continuous for PIDs except for CIP, which is centerx2.
*NB When you write out a block to the library for other people to use,
put all of it on the 0 layer. In this instance you can make centrelines colour by name and
linetype not by layer. The advantage of this is that when someone brings it into a drawing, they
can put the block on a layer and it will show in that layer’s colours.
Plans and Elevations
These should always be in line with each other, ie if a vertical construction line is drawn through an item in the plan view, it should also go through the corresponding part on the elevation. This usually means that the view to the left of the plan view has the floorline running vertically up the page.
To make this view easier to work on just rotate your UCS by -90 degrees and issue the PLAN command. A lisp routine called RO90 will do this
automatically.
The commands are UCS, Z, -90, enter, Plan, enter.
Entity Creation Modes
Entity Mode
Colour Bylayer
Dimension line colour White
Dimension extension line colour White
Dimension Text Colour Bylayer
Dimension style "Standard"
Linetype Bylayer
Textstyle Standard
Dimension Variables, and System Variables
1. Ltscale will initially be set at 4 for the prototype drawing so that dashed lines show up.
2. Mirrtext should be set to 1,because you would never want mirrored text.
3. Dimscale will be set to 1 so that if you are starting a drawing at 1:1 you will not need to reset it.
Note that contrary to a lot of common practice, the units are set to 3 decimal places; not zero places as many people set them. The logic in this is that when machined items need 3 decimal places you do not need to reset the units. For normal whole dimensions, ACAD conveniently suppresses the trailing zeros-see the dimzin variable.
A noted drawback of this is that when you are dimensioning a hole in the middle of a piece of 75 wide flat, the dimension will come up as 37.5, giving rise to a tolerance of +/- 0.1mm which is clearly not desired. The fix of course is to enter the dimension manually at the prompt.
Linetypes
Use standard Autocad ACAD.LIN
Text
Heights and pen widths will be:
Entity Height Penwidth Colour
All normal text 3mm 0.3mm bylayer
Large text 4mm 0.5mm bylayer
Fonts
Use Arial
Scales
Category Recommended Scale
Enlargement scales 50:1 20:1 10:1
5:1 2:1
Full Size 1:1
Reduction scales 1:2 1:2.5
1:5 1:10
1:20 1:25
1:50 1:100
1:200 1:500
Item References
Shall use numbers, not letters. The text height will be 5mm high .The circle to be 10mm diameter.
Block Library
These are kept at
Various categories are used in this folder eg bearings\saeco
If drawing say a motor, have a dimensioned drawing showing 3 views,
plus separate plan, side and end views with no dimensions on.
Be verbose with filenames, eg do not put "150kw motor", put for instance:
"Electric Motor-Teco-315s-85r.-plan - 2D"
Issue of Drawings
Only the project engineer may issue drawings. A document transmittal (standard form) must go with the drawings and a copy kept in the job file. All drawings must be stamped as to their purpose e.g., construction, for information, for tender etc. The project engineer is responsible to see the drawings are checked in respect to design and dimensioning, before issuing any drawings. The project engineer must sign all drawings issued. A copy of any drawing issued is to be kept on a stick file specific to the job, while the job is in progress. Finalised drawings should be stored in the drawing cabinets.
Sections and Views
On any drawing sheet sections and views start at A and work forwards through the alphabet
Appendix
The following lisp routine sets up the layers for PIDs:
;Program written by Bill Le Couteur
;Auckland NZ
;Rev 0 date 18/8/97
;This program sets up layers
;the idea is that layer names are set ONLY
;by this routine...and this routine is run every time you open a drawing
;so if as a contractor you change employers, YOU ONLY
;HAVE TO CHANGE THIS ROUTINE
(defun c:laysetPID()
(setq the_layer (getvar "clayer"))
(setq layvalves "valves")
(setq layproduct "product")
(setq laycip "CIP")
(setq layequipmajor "Equipment Major")
(setq layequipminor "Equipment Minor")
(setq layinstruments "Instruments")
(setq layinstrumentscontrol "Instruments-Control")
(setq laytext "Text")
(setq layservicesgas "Services-Gas")
(setq layserviceschem "Services-Chemicals")
(setq layservicesliquids "Services-Liquids")
(setq layservicescair "Services-Compressed Air")
(command "-layer"
"m" layvalves "c" "33" layvalves
"m" layproduct "c" "1" layproduct
"m" laycip "c" "6" laycip
"m" layequipmajor "c" "7" layequipmajor
"m" layequipminor "c" "252" layequipminor
"m" layinstruments "c" "7" layinstruments
"m" layinstrumentscontrol "c" "7" layinstrumentscontrol
"m" laytext "c" "7" laytext
"m" layservicesgas "c" "130" layservicesgas
"m" layserviceschem "c" "111" layserviceschem
"m" layservicesliquids "c" "145" layservicesliquids
"m" layservicescair "c" "213" layservicescair
"m" "TEXT" "c" "120" "TEXT"
"s" the_layer "")
(command "-laYER" "t" "*" "")
(command "-laYER" "unlock" "defpoints" "")
(setvar "blipmode" 0)
(setvar "ltscale" 4)
(command "regenall")
(setvar "CMDECHO" 1)
(princ)
)
Monday, April 26, 2010
Process and Instrumentation Diagrams-P & IDs.
You can have too much of these. I've been doing a few in the last week or so, and I'm just about all PIDed out. Where I'm working they don't have a standard, so we went with a bunch of symbols that the engineer liked the look of on a previous job. He did not particularly like the ones that I have posted on my site at http://bilrocad.com
There seems to be all sorts of ways of doing a valve unsurprisingly: the ones on my site have little bits of line on the ends of the valves, and they have actuators built in. On his ones, the actuators come as a separate block. Some of them have invisible attributes, some don't.
They are also plainly "old autocad" in that there are no dynamic blocks at all. I have not been a fan of dynamic blocks for normal drafting, but I think they might be the best for PIDs.
If I get enthusiatic enough, I hope to post a set that could do pids.
It looks like a fertile field for lots of lisp macros. On that springs immediately to mind is a routine where you specify 2 points and a line is drawn between the two with maybe a continuation tag at one end and a valve in the line, already inserted.
You can pay for such things, but it seems most people don't, preferring to slog it out with plain Autocad.
There are all sorts of ways of doing pids- I like the tanks drawn in a heavy line-the engineer likes them in grey or very light so that the lines are the emphasis.
Anyone interested in a CAD standard? I have a very lightweight one that just covers the basics.
Maybe next post......
There seems to be all sorts of ways of doing a valve unsurprisingly: the ones on my site have little bits of line on the ends of the valves, and they have actuators built in. On his ones, the actuators come as a separate block. Some of them have invisible attributes, some don't.
They are also plainly "old autocad" in that there are no dynamic blocks at all. I have not been a fan of dynamic blocks for normal drafting, but I think they might be the best for PIDs.
If I get enthusiatic enough, I hope to post a set that could do pids.
It looks like a fertile field for lots of lisp macros. On that springs immediately to mind is a routine where you specify 2 points and a line is drawn between the two with maybe a continuation tag at one end and a valve in the line, already inserted.
You can pay for such things, but it seems most people don't, preferring to slog it out with plain Autocad.
There are all sorts of ways of doing pids- I like the tanks drawn in a heavy line-the engineer likes them in grey or very light so that the lines are the emphasis.
Anyone interested in a CAD standard? I have a very lightweight one that just covers the basics.
Maybe next post......
Thursday, April 22, 2010
Video Driver for Autocad Fun...not
As always with a new version of Autocad (R2011) , it is a good idea to update your video driver.
I am lucky enough to have a quadro FX1500, so I duly updated it.
Somewhere along the line, and I'm sorry I cannot remember the exact sequence of steps needed, this all came unstuck. I had text that disappeared after moving, slow everything, viewports that went all funny. Just beore I thought to blame Autocad, I decided to check 3dconfig. There it had a choice of 2 drivers- One Autocad and one that looked like an invdia one.
I changed to Autocad and all was fixed.
Hope this helps someone!
I am lucky enough to have a quadro FX1500, so I duly updated it.
Somewhere along the line, and I'm sorry I cannot remember the exact sequence of steps needed, this all came unstuck. I had text that disappeared after moving, slow everything, viewports that went all funny. Just beore I thought to blame Autocad, I decided to check 3dconfig. There it had a choice of 2 drivers- One Autocad and one that looked like an invdia one.
I changed to Autocad and all was fixed.
Hope this helps someone!
Saturday, April 17, 2010
The disappearing draftsman, slips and trips, and DS and DIMLO
First, The Disappearing Draftsman. Last week I had an interesting viewpoint explained to me by an engineer I'm working with. He had gone ahead and done his own PID's, but needed me to knock them into shape so that they would be presentable, which took a day to do. I'm not sure how long he spent on them, I would imagine at least 4-5 days.
He explained that he found that he could use Autocad as a faster, easier way of producing a sketch of what he wanted than doing a hand sketch. Plus there was an added advantage that the draftsman was only required to do a short "tarting up". The last place he worked, there was a proper drafting department, and they were probably grumpy that he was doing part of their work.
Here at his new work, there is no drafting dept (only me, 2-3 days a month!). So he has to manage somehow.
I have done a few PIDs, but would hardly call myself an expert, so I was interested to hear his take on how they should be done. He reckons, at the quotation stage, you just insert symbols, and leave it at that. You do not use symbols with lots of hidden attributes so that at a future date you can extract a full Equipment List from the job.
The generation of tag numbers, he said, should be the preserve of the Electrical guys, who make a large database. When they have done their thing, and the job is a go, then you can put the tags on.
Slips and trips: I recently had a reasonably complex design to draft. It was a "bag massager".
I came unstuck in one of my drawings: the 20mm plates welded onto a 100x100 axle, somehow got moved by 100mm, this was only in the detail drawing- the main ass'y drawing was correct.
Which made me think: could this have happened in Inventor? Probably not. But I'm stuck with Autocad, so what could I do to prevent this happening again? My only idea is that I make it policy with any assembly to xref in all the parts.
DS and DIMLO: Yet another engineer, at a different plant, has arrived, and he seems keen on doing his own drawings. That is OK by me, because less time working=more time living. He seems pretty good, just a little polishing required in the dimensions department. Namely, he had large arrows and tiny text on his dimensions.
I explained to him the system I use-but I'm not sure he was at all in favour of it, which is to use 2 lisp routines, DS.lsp to set the text height and DIMLO.lsp to insert, then erase a block that has most dimensions styles a mechanical draftsman might need.
In the past done I have done things differently-see a previous post about zero height text.
Here are the two routines:
DS.lsp:
;This routine sets up for text to be right height
;By Bill Le Couteur
(defun c:DS()
(setq skale (getreal "Please enter the plotted scale: "))
(command "-style" "STANDARD" "ARIAL" "0" "1" "0" "" "" )
(if
(tblsearch "style" "R1")(command "-style" "R1" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R1-25")(command "-style" "R1-25" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R2")(command "-style" "R2" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R5")(command "-style" "R5" "ARIAL" "0" "1" "0" "" "" ""))
(setvar "MIRRTEXT" 0)
(setvar "DIMSCALE" SKALE)
(setq the_textsize (* skale 3))
(setvar "textsize" the_textsize)
(setvar "dimassoc" 2)
(princ))
The nice thing about this is if you have an existing drawing an someone has used the style R5 say, then you can change that at the same time as well.
Here is DIMLO.lsp
;This routine sets up for dims and text;
By Bill Le Couteur
;imports a dummy block containing a set of dimension styles
(defun c:Dimlo()
(command "-insert" "c:/cad/library/symbols/dimension styles" "0,0" "1" "1" "0")
(command "erase" "l" "")
(princ)
)
A very simple routine-I have no idea why Autodesk don't have a magic button that does all this...
Of course, many will argue that you need to set up your prototype drawing nicely, with all the needed scales and the text the right size, and this is correct, except what happens when you change scales? As well, if you purge the drawing your nicely setup scales that are not used are ditched, so if you want to use a 1:20 dimension style, it won't be there.
He explained that he found that he could use Autocad as a faster, easier way of producing a sketch of what he wanted than doing a hand sketch. Plus there was an added advantage that the draftsman was only required to do a short "tarting up". The last place he worked, there was a proper drafting department, and they were probably grumpy that he was doing part of their work.
Here at his new work, there is no drafting dept (only me, 2-3 days a month!). So he has to manage somehow.
I have done a few PIDs, but would hardly call myself an expert, so I was interested to hear his take on how they should be done. He reckons, at the quotation stage, you just insert symbols, and leave it at that. You do not use symbols with lots of hidden attributes so that at a future date you can extract a full Equipment List from the job.
The generation of tag numbers, he said, should be the preserve of the Electrical guys, who make a large database. When they have done their thing, and the job is a go, then you can put the tags on.
Slips and trips: I recently had a reasonably complex design to draft. It was a "bag massager".
I came unstuck in one of my drawings: the 20mm plates welded onto a 100x100 axle, somehow got moved by 100mm, this was only in the detail drawing- the main ass'y drawing was correct.
Which made me think: could this have happened in Inventor? Probably not. But I'm stuck with Autocad, so what could I do to prevent this happening again? My only idea is that I make it policy with any assembly to xref in all the parts.
DS and DIMLO: Yet another engineer, at a different plant, has arrived, and he seems keen on doing his own drawings. That is OK by me, because less time working=more time living. He seems pretty good, just a little polishing required in the dimensions department. Namely, he had large arrows and tiny text on his dimensions.
I explained to him the system I use-but I'm not sure he was at all in favour of it, which is to use 2 lisp routines, DS.lsp to set the text height and DIMLO.lsp to insert, then erase a block that has most dimensions styles a mechanical draftsman might need.
In the past done I have done things differently-see a previous post about zero height text.
Here are the two routines:
DS.lsp:
;This routine sets up for text to be right height
;By Bill Le Couteur
(defun c:DS()
(setq skale (getreal "Please enter the plotted scale: "))
(command "-style" "STANDARD" "ARIAL" "0" "1" "0" "" "" )
(if
(tblsearch "style" "R1")(command "-style" "R1" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R1-25")(command "-style" "R1-25" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R2")(command "-style" "R2" "ARIAL" "0" "1" "0" "" "" ""))
(if (tblsearch "style" "R5")(command "-style" "R5" "ARIAL" "0" "1" "0" "" "" ""))
(setvar "MIRRTEXT" 0)
(setvar "DIMSCALE" SKALE)
(setq the_textsize (* skale 3))
(setvar "textsize" the_textsize)
(setvar "dimassoc" 2)
(princ))
The nice thing about this is if you have an existing drawing an someone has used the style R5 say, then you can change that at the same time as well.
Here is DIMLO.lsp
;This routine sets up for dims and text;
By Bill Le Couteur
;imports a dummy block containing a set of dimension styles
(defun c:Dimlo()
(command "-insert" "c:/cad/library/symbols/dimension styles" "0,0" "1" "1" "0")
(command "erase" "l" "")
(princ)
)
A very simple routine-I have no idea why Autodesk don't have a magic button that does all this...
Of course, many will argue that you need to set up your prototype drawing nicely, with all the needed scales and the text the right size, and this is correct, except what happens when you change scales? As well, if you purge the drawing your nicely setup scales that are not used are ditched, so if you want to use a 1:20 dimension style, it won't be there.
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