solid offset linetype

[Three D]

hi. does anybody know if it is possible to create an autocad (2010) linetype that draws an offset of the line you are drawing while also giving the offset line a width and keep both geometries linked as one.

 

we regularly do planning and legal drawings that require areas to be outlined in red. our normal procedure would be to draw a zero width polyline in the correct position and then offset it by say 0.5m (depending on the plotted scale) and then give the offset line a polyline width of 1.0m and change the colour to red. this works fine except that the boss thinks there are too many risks with this as somebody could use the red offset line to calculate site areas and end up with the wrong value. as per usual, despite that fact that he cannot himself use the software, he thinks this is a very basic requirement for any sort of mapping requirements - and he's entirely correct i suppose.

 

procedures and workflows when done correctly work fine but they can sometimes leave you exposed to user interface error!! i've always avoided the area calculation error above because i'm used to the prodedure and layer all my work correctly but i can see where somebody not familiar with the software/procedure might see it differently.

 

any feedback would be very much appreciated.

 

thanks.

[Cad64]

Try using a Multiline. Check your Autocad Help files for information on MLINE and MLSTYLE.

[neko]

yup - that would be the first time in my entire autocad life that i've thought that multiline (MLINE) would be a good idea.

[Three D]

thanks for your help Cad64 but MLINE/MLSTYLE is no real help. I can get a mline that looks like what we want but what i was hoping for was when i draw or create a polyline which may consist of lines and arcs that i can change it to a linetype that automatically creates an offset polyline with a width and when somebody checks the area of the polyline with the width it would give them the correct area of the originally drawn polyline and not the offset one. simple but complicated i suppose. i'm fairly sure it can't be done straight outta the autocad box but i needed to check before i went back to the boss. eveytime he puts the "can autocad not do that?" question to me he makes it sound so simple that i begin to query what i know or what i think i know about autocad and then doubt sets in and i begin to wonder if such a feature has existed for ages and i was unaware of it. in all cases though that turns out not to be the case and despite him making it sound like such a simple requirement it never exists.

[erickdt]

Would it be very difficult to manually offset the polyline, draw lines to close the shape and make it a region? That would give you area/sqaure feet I think.

 

E

[Three D]

thanks erickdt but that wouldn't give the boss what he wants. the way we work already works fine (to me anyway and i have 18 years autocad experience) but my boss who doesn't use the software thinks differently. he wants to draw one thing (a closed polyline) but for it to display something different (an offset of the closed polyline) yet give you the area of the original thing (the original closed polyline). not possible me thinks.

[neko]

sounds to me like you'll just have to offset the polyline and change the linetype manually.

 

you can change the polyline width using PEDIT, but i have a routine for quickly doing that as well.

 

i really don't think you'll find any automated solution, and it doesn't sound like much work anyways (unless i'm missing something).

[Cad64]

You can't select one object and have it display the properties of another object. That's like saying I want to eat an apple, but I want it to taste like a cheeseburger.

 

Why do you need to select the offset line anyway? Why can't you just select the actual line?

[neko]

just thought of something that might help.

 

in the offset command, you do have an option of whether the new offset object is the same as the original, or takes on the properties of the current layer.

 

if you set it up that way, you could save yourself some time changing the layer properties. with a new layer, you could then easily isolate the new polylines and give them width with one PEDIT command.

[Three D]

no, i agree neko. there is no automated solution, the current solution takes little effort and the whole thing is a pointless exercise as usual thanks to my boss.

 

i'm sure its similar all over the world but in ireland when doing a planning application the site has to be outlined in red. we draw a polyline around the site and then offset it and change the width to 1.0m and the colour to red. job done. but my boss reckons its a recipe for disaster because somebody will use this drawing to get the site area and the will do this by taking the area of the offset redline which has been offset 0.5m from the correct position thus giving an incorrect inflated value for the site area. i avoid this by naming the original redline layer C-REDLINE-ACTUAL and the offset redline C-REDLINE-OFFSET and I tell all staff about this. last week i sent around an email telling people to make sure that when they draw something outlined in red that they outline it and don't online or inline it because that is a completely different thing altogether. i explained to them that they should layer name accordingly to avoid confusion. the boss spotted the email and was aghast that autocad could not automate this and take away any risk from us silly cad users. he used software 30 years ago that he reckons did all the stuff that autocad cannot do. he struggles with his iphone so i reckon he may be a bit dillusional. occassionally though hes bang on the money and autocad should be able to do simple things that it cannot do. but i suppose all bosses are a bit like that.

 

"...........sure it's all done in autocad now anyway............"

[neko]

lock the layer ?

 

if only autocad had a password protected lock layer option, then you could be sure...

[Three D]

You can't select one object and have it display the properties of another object. That's like saying I want to eat an apple, but I want it to taste like a cheeseburger.

 

Why do you need to select the offset line anyway? Why can't you just select the actual line?

 

 

i hear you. i hear all of you. we can always select the actual line but the fear (not my fear) is that somebody will select the other line either by mistake or stupidity. my boss loves saying "why can't autocad do this or that?"

 

i suppose all we would really need is an additonal option with the pedit command that allows you to give a width to the polyline but with the options of offsetting the width inside or outside the original line. the more i think of it the more it seems such a simple option to have.

[Cad64]

After you offset the lines, make them a block. You can't run the AREA command on a block, so they would have to explode the block in order to do this. And if they do that, then that's their fault.

[Cad64]

i suppose all we would really need is an additonal option with the pedit command that allows you to give a width to the polyline but with the options of offsetting the width inside or outside the original line. the more i think of it the more it seems such a simple option to have.

 

You've just described the Multiline.

[Three D]

no i haven't. you cannot check the area of a multiline or have arcs as part of a multiline. its a completely different type of entity to a polyline.

[Cad64]

True, multilines are limited, but as far as I know, that's as close as you're going to get to what you want in Autocad without a custom lisp routine of some sort.

 

I would just draw the main polyline, offset it, change the properties accordingly and then make them a block. That way the main polyline will be accessible to the AREA command but the offset lines will not.

[neko]

True, multilines are limited, but as far as I know, that's as close as you're going to get to what you want in Autocad without a custom lisp routine of some sort.

 

I would just draw the main polyline, offset it, change the properties accordingly and then make them a block. That way the main polyline will be accessible to the AREA command but the offset lines will not.

 

...and make the block unexplodeable.

 

that's what you meant to say, right ?

 

i normally would never set a block that way myself, but this does seem like the right situation.

[Cad64]

...and make the block unexplodeable.

 

that's what you meant to say, right ?

 

i normally would never set a block that way myself, but this does seem like the right situation.

 

Sure, as an extra measure of security, you could make it unexplodeable.

But it's easy enough to reverse that, so if they really want to, they can still explode it.

[neko]

Sure, as an extra measure of security, you could make it unexplodeable.

But it's easy enough to reverse that, so if they really want to, they can still explode it.

 

how do you make an unexplodeable block explodeable ? it's not in the properties, and it's not a system variable that i can find.

[Cad64]

Open the block in the block editor, BEDIT. Once you have the block open, don't select anything, just open the Properties palette, scroll down to the bottom and change the "Allow Exploding" option to Yes.

[neko]

didn't know that (obviously) - thanks.

 

i don't use the new block editor if i can avoid it. i have double-click set to REFEDIT.

[Three D]

thanks for all your input guys. i'm aware there are plenty of ways to workaround the risk none of which would please my boss when to him the solution is very simple and should be available in autocad from version 2000 onwards. you should hear him lament over this CAD system he used 25 years ago - it sounds like the best piece of kit ever and did everything you could possibly expect it to do.

[Cad64]

you should hear him lament over this CAD system he used 25 years ago - it sounds like the best piece of kit ever and did everything you could possibly expect it to do.

 

You should ask him where this wonderful piece of software is today. If it was so great and did all these extraordinary things that Autocad is unable to do, then where is it? What happened to it? I would certainly be interested to find out what program he's talking about.

[Three D]

no point. i'm sure it didn't do a fraction of the stuff he remembers it to doing.

[Cad64]

You might want to sign up over at CadTutor.net and ask one of the lisp guru's to write a custom routine for you. If it can be done, they can do it.