Drawing a Roof Structure Using 3D solids in Autocad

Where I work as an architectural draftsman, I recently had to draw a renovation that had a nasty roof on it.  Not that nasty, but the question was, if a wall was removed, will the roof fall down?

By drawing in 2D you can make a few close guesses, so on the weekend I cranked up dear old Autocad to see what it would be in 3D.

The underlying drawing was not accurate, which accounts at least for some of the shoddy drafting!

More of an attempt to understand the structure. 

Last thought....how much of a drama to produce this in Revit?

The positions of the rafters were found from a set of solid planes that were representative of the purlins layer, not drawn as individual purlins, but as a set of intersecting planes.

Drawing sections and elevations in the same place

Continued.
I have to admit defeat on this one. Apparently on a recent job we had a coved ceiling on the elevation, and naughty me drew a standard section, using my separate is good technique, leading my boss to point out that had I combined the two, I would not have made that error. The builder coped somehow.

Score one for the boss.  He also said my technique of separating out the building plan from the site plan was annoying for others who wanted to work on one of my drawings. So can I please put the eggs an ham in the same frying pan?

So, ok, I will just have to cope somehow, taking a productivity hit. Every time I open up Revit and work in 3D, it just feels a lot nicer way of working anyway.

Mired in laziness

 Layers

 A few things are niggling me. One is layers.  Seems like they multiply like rabbits.  If you are drawing a single level house it is nice to have a certain set of layers. If you are doing a reno, yet another set.  Don't get me started about a 2 storey house because that is yet another set.

Oh yeah, what about that 3 level mansion?  How about commercial stuff?

My dubious approach has been to run with what has gone before.  Which is find a drawing that is nearest to what you are going to work on and do a save as of that.  Trouble is, every time you do a drawing you have to insert blocks, and here they all come: the rogue layers!

Before you can blink, seems like just too many layers.  My layer management system is very crude- I have scripts that work on the idea that anything on the ground floor is labelled something like
GF-DIM.   Which begs the question:  why have one layer for dimensions and one for text?  Seems crazy to me.

I would love to have a couple of days to sort them out, but too busy working.  One thing I am trying though is a scheme where all layers are the same, across all types of work.  To this end you end up with layers like GF-NEW EXT WALL, which is pretty plain in it's meaning.  This would enable me to use the same scripts for all work.

The problem can come when you want say a drainage stack to appear on say the second floor framing plan and the ground floor as well.  Which can be got around in the script, but it means that layer must exist or the script crashes. I have started work on a script that blasts the drawing with all  the layers I want in the colours I want.

 Working Styles

 I am slowly evolving a work style that is supposedly working smarter, but was probably the lazy me thinking of the easy way out without giving things too much thought.

My technique is to have a plan view in the middle of the drawing, which has all the building stuff on it, no site stuff.  Above this, but lined up with it is one of elevations, upside down of course, then the site with the house outline on it.

You might say not a good plan as the outlines now have to be updated each time something changes.
True, but if you ever reuse that building for a different site it makes it a straight forward job.  Which you could counter which:  No, it is better to have the site mixed in with the building and just manage your layers better. To which I say: It is better to get into model space and get on with the job, and not horse around with layers.

Same with sections: No, to having them plastered on your elevations!  Just gets tedious filtering layers endlessly every  time you want to work on something.

Using Autocad LT to draw houses

You may be aware that I have a copy of Revit, and have been trying to come up to speed with that, which is a bigger task than you might think.  Any fool, (includes me!) can leap onto Revit and produce a sort of a drawing of a house.  The fun begins when you find you want a window with a brick sill, and you cannot find one in  Revit City.

Recently we had a job where the plan of the house was in the shape of an S.  Which in Autocad LT meant hours of me tediously drawing windows which were oblique to the view.  In Revit, no worries, just insert them in the wall and the go choose your view . Hmmf! Not to mention the lack of real customer engagement as any nicely drawn elevation is all very professional looking, but as far as I can see does not get the customer to appreciate what the house will look like in reality.

So, what is the answer? As usual, a lemon.

That Revit is where it at, is further enhanced by an add-on for Revit called Enscape, which allows real time rendering, as well as being easy to use.  Yes, you can do renders in Revit, but the sky always looks unconvincing.  Trouble is, it costs $45.00 per month.

To 2D or 3D for an architectural detail

First of all, this is not my design.
I am still at a learning stage when it comes to special details such a this one.
The job is a re-clad, and this little area turned out a bit of a challenge.

At work, I did this in 2D, and this is the result:

All the 3D bits were done by eye.

Thinking this might have been easier to do in 3D, I came up with the following:

How it goes...

Just need to revise these drawings....just need a gas bottle on the plan view.
....just need an easement boundary on the site plan of that one.

In my mind: This should only take about 10 minutes.  Wait, I'm always out, so
multiply by the "Bill Factor"  This is about 3 usually, so say 30 minutes.



Decision: I need the following:

1. A button that inserts a revision triangle

2. A button that inserts a polyline across the whole drawing and is on the
defpoints layer so it does not print but anyone looking through the layout tabs
can quickly tell which layout tabs were revised. So they do not get confused the
next time the drawing set gets revised ;)

3. A button that puts a draft stamp on the drawing.

An hour later, done.

All this fiddling around with buttons adds another 15 minutes to that hour.

Previously I had some of these several mouse clicks away in a menu pull down.




So why are these not a built in part of Autocad?  Even if it was just a
ctrl key + letter?

Another thing missing: Automatic bubble inserting, eg, you have bracing which needs
a series of sequential numbers in little circles.

We have LT, so I had to get creative here - no lisp on LT.

What I did it was create 24 little blocks each with a circle and a number.
Then a macro that inserted them one after the other, something along the lines
of -insert;"c:/cad/library/bubbles/bubble1.dwg";\;1;1;0;  repeated 24 times.

Again, how come we do not have this sort of thing built in?

A cautionary tale.....

While seemingly not related to Autocad, it actually is.

Every sensible person knows that if you use a computer, you should do a backup now and then in case all turns sour.

I thought that I had been a good boy in this department, but it turns out, not so good.

One of my recent jobs was a set of apartment houses and as such kept a pretty good backup.
Of my lisp routines....maybe not so good!

So when my operating system finally kicked the bucket (Windows 10? who knows?), I took it to the man, thinking he might be able to resurrect it with some magic tricks.

But no. All too difficult  it seemed, so it was decided he was able to save the data on the hard drive and reinstall Windows 7 ("your computer is maybe not geared up for Windows 10"...)

Ok then.  Well it would have been, but he only copied what was in Documents, deleting the other gazillion gigabytes on the rest of the drive!

So....take a look at your storage, and over do the backups!

I have found a system of backwards date names for the files is good, for instance:
20160907 Backup, which means done in 2016, 09 means September and 07 is the day.
When you have a lot of these folders, they will sort themselves in date order in Windows Explorer.

Them there pesky contours...

You have a site plan, onto which you have put spot levels obtained from a field trip to the farm.

The need now, is to convert these to contours.  To do this accurately, you have to calculate the distance between two spot levels and then calculate from them, and the level information.

Which is a lot of calculation and fiddling around.

So, another lost weekend later I have a lisp routine that does this.  No doubt someone has already done something similar, but at least I can say I did it my way!

In the pic below you can see the spot levels in grey, and the contour text in red-in NZ we do them every half a metre.

Of course, you have to draw in the contour lines in afterwards, but the points are accurate, not guesses.

The next routine that flows from is where you pick two spot points, and then a third point, and the elevation of that third point is marked with an X and it's elevation put on the defpoints layer.

You can see the demo at https://www.youtube.com/watch?v=_F8ke6Ogw7o