That Roof Object again

Ok I am now about to contradict everything I have whinged about with this 'object'. I now know how to add a vertex to the roof object!! It's true - it can be done. Wow! I'm blown away. And the secret is so simple it uses autocad commands! No wonder I didn't find it until now. Did you know about this?? Why didn't anyone tell me? Is this common knowledge?? If so then I'm a red-faced carpet snake!

Anyway I am going to share the secret with you!

One of the things I have enjoyed about doing this blog is that I have taken the time to stop and actually work thru the issues I have come across and in a way that I can explain to share with others. So many things have dropped into place as I've tried to organise my chaotic ways. Working for yourself has advantages but it also has downfalls. Now to that roof.

Something that has puzzled me is that essentially the roof object is programmed mathamatics and should be predictable. It may have limitations but they should be able to be understood and worked within or around. When using the roof object it can do some strange things but they should be able to become known and anticipated.

Hey before I get into the roof object again here's a great thing you can get into.

Great Daily Tips for AutoCAD (and ACArchitecture)

I just recently signed up for tips from Mike Williams, an experienced AutoCAD user and (I think) of ACArchitecture as some of his tips are for ACA. One of the strengths (and weaknesses) of ACA is it's AutoCAD base and we all use heaps of AC methods as much as ACA.

Great bite sized tips in your email everyday! I've already learnt a couple of new tips and been reminded of tips I've forgotten.

Oh and the roof object . . . . . . . . . come back in a couple of days . . . . . . it may blow you away like it did me!

aecRoof Object - Part 4

Now I am talking mainly residential roof's here but I don't discount the commerical roof, with many commercial buildings built using residential practise. You may need to refer to the earlier parts of this series 1, 2 & 3.

The simple Cutout for the roof object is just a matter of tracing the outline of your roof and editing the edges (right click option) of the cut out portion and changing the overhang and the slope to 90. Just remember if you miss a point (vertex), you have to recreate the whole roof!

What about the Cutback eave? I showed this in my wall example, having to edit my external cavity wall to cater for a cut back eave. This happens not infrequently here in West Aus. So how do we wrestle the roof object into cutting back the eave and showing the eave in one straight section. You would assume that you should have two end points and a point (vertices) for where the roof eave changes from overhang to none but you will be wrong. The Roof object can't do it and your eave goes strange. You need to have an extra point and the extra edge has to have 90 degree slope. That's illogical to the roof shape but it works. Once constructed you need to drag your points very close together so that the raking portion of the eave appears at right angles to the roof pitching line for a spandrel to end the eave overhang.

What about different plate heights? Can the Roof Object handle this? Very easily!
Construct your roof at your main height. Select your roof, right click and select 'Edit Edges'.Select the edges you want to raise and enter the new pitching height. You are done.
But remember that the roof object can't overlap itself UPDATE - WRONG so for e.g. the eave can't overlap the lower roof portion. So how can you do that? Resort to slabs? Chicken! Here's a method that takes just a little planning.  WHILST this technique works, being able to overhang itself is probably a better option as the valleys will self heal at the right height without you have to input.

Create the main roof and trace around the valley connecting the main roof to the raised portion. These connecting edges will get a 0 overhang and a 90 slope. Now create a second roof to position into the breach and you are done. Your new roof can now overlap the main roof and there are no unwanted lines on your drawing.

Tip: As I've pointed out before, don't worry about getting this cutout right for your design development stage. Just overlap roof objects as required to get your outer shape as you need. Once the design is final you can plan & trace and replace so your sections will look correct too.

Well that's probably as many tricks as I know to using the aecRoof Object without resorting to slabs. UPDATE - LOL Hopefully I've helped you to be able to use it more extensively, at least in the design process and be able to get it to look how you want.

Oh and I have added some more detail for a Dutch Gable and some interesting tips for gable infil and about the behaviour of the aecRoof object as a barge to Part 2 of this series. It's in the centre of the post if you don't want to read it all again.

Happy Roofing!

I've developed a Lisp !

It'th True! I'm slowly (very) developing a lisp. I have finally dived in and started to learn AutoLisp and enjoying learning my first programing language. Ok I did type in a random dice program in basic but that shouldn't count. And yes even VBA has been pushed aside in Autocad 2010 but Autolisp should be here for years to come. I've been trying to reconstruct a useful program that allows you to pick 2 corners of a room and it prints the size in metres in the centre of the room. Great for marketing plans. Turned a functioning program into one that simply delivers "nil". Some work to do!

AUGI is a great resource for learning lisp and has a newsgroup and some great tutorials you can download. Of course there is Adesk's own newsgrops.

I also plan to get my thick head around OpenDCL, an open source version of the programming of the dialogue boxes that you use.

My long term goals in case anyone (anyone?) is interested.

1. Program to facilitate levels within one drawing. Should be fairly simple. Manipulate layers, elevation and display rep. Need to automate text & dims to the appropriate level as well. Got most of it sorted in my head and manually tested and satisfied with outcomes.

2. Program to enable one touch to shuffle a multi-building drawing (either blocks or x-ref's) to a level assigned in a tag and toggle back to 0 elevation. Multiple unit developments on a hill side can't display plan view and create elevations at the same time if cut plane no longer intersects houses at different levels.

Let me know if you are interested, could help me, want to laugh at me or have any comments that could help.

(setq salute "best to ya")
(princ salute)

aecRoof Object - Part 3

Here's a pic showing the roof object creating a number of different roof shapes. You may need to read at least part 2 to get what I am showing here and how to get there but in part 1 I am promoting the Roof Object as a usable tool even for construction drawings!
The round (2 pitch) roof was based on a 16 side polygon and how they usually construct it anyway though usually 8 sides. The flat top (name?) was created using 2 pitches and then adding a third 0 slope roof as similar to what I describe here. The Pizza hut roof is done using the double slope roof (check the properties pallete) as can the Mansard roof if the pitching is on all 4 sides (not 2 like I've shown).
The Dormer is simply another roof (object) sat above the main roof. The trick here is to create a 5 side roof shape, with the back planted end having 2 (triangular) sides with no overhang and the slope set to 90. UPDATE - see technique for dormer roofs and other holes. The roof object cannot have holes so yes there will be roof in the middle of dormer and won't work for sections thru' here. For a schematic section you could use a masking object or simply edit the section and delete the lines. That may even possibly get you thru' a construction drawing as well.

The floating or planted Gable is again another simple roof object with 5 sides. The trick here is the 2 sides with slope are too small to be seen so it appears to be a triangle. The VisionRez roof can do this slope without a length being required which is very smo
The Gablet or Dutch Gable (Gablet-uk) along with the Mansard, Half Hip and derivatives can be created using the technique describe in part 2. via editing edges.
The Skillion roof is the most simple but not obvious with the roof object. It would appear to be native to a slab. But aecSlabs behave differently (displayReps) and so I will use the RO instead.
Trick is to create a 90 slope roof to start with and only add a slope to the one side edge. It can also turn corners and wrap around a house, even completely around. To get a verandah roof all around a house (with a hole in the middle for the house) create one roof up to the hip and then another to complete. Connecting at the hip end will disguise the use of two objects and there will be no unwanted lines in plan, elevation & model. (UPDATE: If you create a full square roof and add a second pitch at 0 to one edge at a height between the pitch line and ridge, you will get a hole. This is demonstrated in my file posted at AUGI and Adesk NG.

Hopefully you can see that the roof object has some versitility. You may well need to revert to slabs to do a complex roof but the RO can certainly go further than what may be immediately obvious. I seriously believe that with a little tweaking by the Autodesk team, the roof object could be a great tool for residential roof's. As it is - it's almost there! I don't care for edge styles as I am happy using a wall style for that But it does need ;

1. Ability to add/remove vertices (critical) UPDATE - it's there but hidden.
2. Ability to cut holes (ok not so critical) UPDATE - reasonable workaround.
3. Styles (ok not so critical but would be nice)

Now that slabs have componants, it may be required in your project and overtake the roof object's usefulness. But again think about how much detail you need and remember that the more complex the model in 3D, the harder it gets to manipulate it and the longer regenerations etc take. Sometimes you just don't need the extra data and can add info to a section (the only place it's required) just as easily.

Next I want to look at when a roof needs to overlap itself and the simple cut out section.

ACA v2010 and roof shapes

Are you searching for blog announcements on the latest version of AutoCAD and ACA?
I have been and there appears to be some exciting things happening in AutoCAD. How they translate across to ACA and how (and if) they are incorporated in the aec tools is to be seen. 'Mesh to solid' could be exciting! Could bring some serious tools to create site development work in 3D which has been sadly lacking. I shouldn't imagine I will do much organic modelling in affordable housing but when that housing is on the side of a hill then it could be useful.
One blog to watch is Shaan Hurley's Between the lines (the inside story).
Shaan mentions improvements to walls (good), stairs(gooder) and structural members (which have lots of other uses). The PN & interface have been touched, the interface probably just phase II of the ribbon (eugh!). The PN - not that I use it but for larger projects it's a great organiser so it will be good to see upgrades to it's shortcomings (phasing, options, timing, multiple buildings). No mention of roof's (sigh!!).

Gambril or Gambrel? Googling it I can see that the name is probably incorrect according to world usage. Americans don't use them (the aussie version) and I don't see examples elsewhere but we use them alot here. So if anyone has a correct name for this type of roof please let me know so I don't continue to show my ignorance online to the world. Or should I just call it a floating gable. That one kinda sounds like it should not touch the main ridge though.

UPDATE:
ok I should have googled it. Wikipedia confirms that my roof shape is known as a 'Dutch Gable' in Aus and a 'Gablet' in the UK. Americans call something else a dutch gable (one of those elaborate rendered gables you see on the hacienda in the old wild west movies). The Gambril or Gambrel roof also known as a Mansard roof is essentially a dual pitched roof. My friend Stuart comments "The roof you illustrate I know as a gablet roof which had its origins over here in roofs prior to around 1500 when chimneys started to appear. Earlier houses would be open to the roof with no upper floor and the fire would be on the ground probably in a central position with the smoke rising up to the exposed rafters and they would form a small gable at the top of the hip which would be left open (no gable wall) to allow the smoke to escape." Well we use them alot here in Oz.

Well now I'm better edjamakated!

Cheers.