Architectural Design Software :
A Comparison of ArchiCAD, AllPlan, and AutoCAD
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Architectural CADD Consultants
The New Generation
There have been three great waves or generations of development of CADD software used by architects.
The first generation, dominated by Intergraph, followed distantly by ISICAD, Accugraph, and GDS, with a few avant-gard programs like SOM CAD (IBM AES), were primarily proprietary (and later, Unix) operating system, hardware intensive programs, where firms essentially hired computer science personnel to draft up designs they did on paper.
The second generation, clearly dominated by AutoCAD, followed distantly by Microstation, and even more distantly VersaCAD, Computervision, and ClarisCAD, with a few avant-gard upstarts such as DataCAD, were primarily microcomputer based 2D drafting programs, where firms set up the lowest levels of architectural draftsmen in separate departments from designers to draft then redline and re-draft projects. Many architects used add-ons with these programs that made it easier to draft plans and details, and through various 2.5D techniques to help generate sections, and elevations.
Simultaneously, an entirely different category of software specifically for designers emerged - which was not even capable of drafting, but only did 3D modeling - represented originally by MegaCADD, SilverScreen, ModelShop, Architrion, UpFront, and now by true solid modelers such as DesignWorkshop, 3D Studio, and FormZ.
Now a third generation of software for architects has emerged that combines the best of the 2D drafting software and the 3D solid modelers, but also more importantly is architecturally intelligent, allowing for an integrated whole building design easily by higher level architects. In this category, in the United States, Arris Software - too far ahead of its time, too expensive, and too poorly marketed - was alone. Later, ArchiCAD, imported from Europe, started to dominate this category. Now that inexpensive microcomputer hardware is more powerful and NT now the dominant development operating system for CADD software, and, at the same time long time computer savvy architects using second generation CADD software are looking for a better, more integrated, approaches to design, this third generation of CADD software is truly about to come into dominance. Thus the timing is right for another import from Europe, AllPlan, which is even more powerful than ArchiCAD or Arris, to enter the US market.
Drawing Aids
All three programs have the usual drawing aids - snap grid, object snap, ortho angle lock (although AutoCAD and AllPlan allow only 90 degrees normally), zoom, pan, previous view, and so on. AutoCAD has keyboard shortcuts, some very strange ones, as does ArchiCAD, which has some peculiar "hidden" commands such as Option-click doing different things in different modes, whereas AllPlan has no keyboard shortcuts at all.
ArchiCAD and AllPlan
Specifically, both ArchiCAD and AllPlan are specially designed with Architects in mind, and give the designer parametrically intelligent tools to build with, such as walls (into which the software knows how to place and modify specific windows and doors), floor slabs (which automatically allow for stairs and other openings), roofs (which automatically accommodate dormers and other intersecting roofs), and parametric macro symbols (furniture, stairs, columns, and other architectural elements that can dynamically change based on parameters). All these elements are parametric, meaning they can all be dynamically changed and will automatically adjust other associated elements based on parameters, i.e. changing wall type and height results in the framing opening around all doors, windows, and intersections, as well as the roof to change appropriately. In order to do all this, both ArchiCAD and AllPlan must be essentially 3D solid modelers with intelligent "wall" entities. The ramification of this is that all plans, sections, and elevations come from the same integrated information. The side benefit in both cases is virtually automatic perspectives, axonometrics, and animation walk throughs. Other benefits to this approach are things that give more information to the designer while he is designing - dynamically updating cost analysis, energy analysis, sun and shadow analysis, and, in the future, structural analysis and building code checking.
Where ArchiCAD and AllPlan differ is in several areas, particularly in 2D drafting, 3D solid modeling, roof design, collaboration, and general working method.
ArchiCADs Background - Limitations and Assets
ArchiCAD is designed to be as easy and simple as possible to use, with a great deal of work happening automatically. In order to do this the developers of ArchiCAD have made many assumptions, hidden the complexity and flexibility from the user, and given the user only four basic building blocks to work with (walls, floors, roofs, and macro symbols), each with associated constraints, which make for ease of use and simplify the parametric interaction. Thus, walls must go straight 90 degrees up, with uniform thickness, though they may have different composite make-ups, and all openings (windows, doors) must be rectangular. (To allow for arched openings there is an easy work-around technique for filling in the triangular gaps between the rectangular openings and the arch.) The feature of this is that placed parametric windows and doors can change very easily. Additionally, if you change a wall from, say, a 5" GWB wall to a 8" block wall, the thickness of the wall and framing around all openings all automatically adjust better than any other program. Floor slabs, though they may be as complex as desired with as many hole openings as needed, must stay flat. The feature of this is that any furniture placed can automatically be set at the height of the selected floor slab of the current story. Only the roof generator can make a sloped surface - which means that it is the only, and clumsy, way of creating ramps, stair handrails, sloped desks, and so on. The feature here is that roof openings, intersecting roofs, dormers, and roof height, are all handled automatically, and that walls can be automatically cut off at the right angled height. The macro symbols are probably the biggest assets of ArchiCAD. The easily visual, and parametrically changeable object library is handled better than any other CADD software available. Creating custom library objects of one's own, however, is a multistep process that is more involved than most other CADD programs, including AllPlan and AutoCAD.
Editing in Elevation
Up to now, the primary limitation to ArchiCAD, by far, was that it was not possible to directly edit, and thus design, in the elevation (side) or section view. To adjust the height of a window (roof, chimney, stair, etc.) relative to something else on an elevation, the only possible way was to go to the plan view, select and type some new numbers, then go back to the elevation and hope the numbers were right (rather than directly using a move type command while in the elevation view). This way of working made ArchiCAD unusable for certain architectural firms. The new ArchiCAD 5.0 now has the ability to change certain elements in the elevation view. Our evaluation of this new ability is not yet complete - we have yet to determine if full rotation, stretching, moving, hole (window) making and so on is possible on all roof, floor, stair, and other elements.
2D Drafting
ArchiCAD is so oriented to doing walls, windows, doors, and other architectural elements and quickly producing floorplans, elevations, and sections, that it has a surprising lack of ability in simple 2D line drafting. There is, for instance, no command or ability to trim lines or cut one line with another, as there is with virtually every other CADD program, nor is there a group type command to move or edit special clusters of lines at the same time. For instance with two crossed lines, the only way to trim them in all 4 ways is to mark their positions, erase them, and then draw two new lines, whereas almost all other programs can do the same thing in two or three clicks. Thus, for drawings other than floorplans that may be required in construction documents, we strongly advise supplementing ArchiCAD with a good 2D drafting program, such as DataCAD, MiniCAD, or AutoCAD.
Automatic Layers
One of the nicest features of ArchiCAD is that all elements are drawn on their appropriately named layer (Exterior Walls, Roofs, Floor Slabs, etc.) automatically. It may not adhere to the AIA Layering Guidelines, but it does it better, and is flexible to accommodate any layering scheme.
Types of Architecture Appropriate for ArchiCAD
With these particular limitations to ArchiCAD's four basic elements, the software is ideal for architects and interior designers of fairly normal conventional buildings - mostly rectilinear, sloped residential style roofed type buildings - such as most single and multi-family housing, small commercial, shopping malls, club houses, and the like. It would definitely not be appropriate for designers into deconstructivism or non-90 degree partial walls or unusual roofs. Designers like Frank Gehry with his fish-shaped buildings, or LeCorbusier with the Cathedral at Ronchamps would find ArchiCAD totally inappropriate. Additionally, because ArchiCAD lacks any sort of reference files or other way for multiple people to easily collaborate across a network, designers of very large buildings (airports, large hotels, etc.) needing a lot of people would be unusually challenging (relative to AutoCAD, Microstation, or AllPlan) to do in ArchiCAD. However, since a large number of architects are sole practitioners doing relatively conventional residential buildings, ArchiCAD definitely has a solid place among the best tools for certain architects.
AllPlans Background - Limitations and Assets
AllPlan is very similar to ArchiCAD, but is designed to be much more flexible. As such, it is more challenging to work with, though still nowhere near as difficult as AutoCAD. Typically, you can work with plan, front elevation, side elevation, axonometric views all on screen simultaneously - choosing one point in one view and the next point in the same command in an entirely different view orientation, as needed, and convenient. Thus, the whole way of working with the software is different from ArchiCAD (where you have to wait for the generation of the desired view) or even AutoCAD (where you would also have to change construction planes before you could add, or move anything). The walls (which include the windows and doors as ArchiCAD does) are a special entity type, but you can convert them into 3D solid objects to cut them into special shapes, and still convert them back to walls so that they automatically perform other operations. For instance, windows can have upper and lower control planes relative or not relative to the wall and its relation to the roof line; they can thus have straight, angled, or even curved tops or bottoms, or align with other dissimilar windows in a way more flexible than with any other CADD program. You could even carve a curved niche in a thick wall and have the wall still retain its wall abilities. Strangely, though, even though everything else in AllPlan seems to change dynamically and automatically, if you were to change a wall type from a 5" GWB to an 8" block construction, it would not change the width of the wall automatically as ArchiCAD does - only the material would change. The roof design method is extraordinary in its ability to flexibly and dynamically change from one type to another, allowing for the most complex roof designs possible - easily - of any CADD program in the industry. To get all this dynamic flexibility there is definitely more work to set up each wall type than with ArchiCAD. This, in fact is a slight drawback to AllPlan, as there really should be a library of a number of standard walls (with associated window upper and lower planes) that could ship with the program. Fortunately, custom wall types can be saved and transferred between projects in an office.
Layer Sets and Reference Files on Network
AllPlan has an excellent way of dealing with layers and layer sets (called "multi-layers") with a single project file for all associated drawings, allowing for any global changes to automatically occur on all coordinated drawings, even by many people across a network. Using a system even better than AutoCAD's "reference files" (similar to Sigma Design's Arris, where each layer is actually a separate file) AllPlan has unparalleled power to help designers collaborate across a network. A drawback of this flexibility is that again, unlike ArchiCAD's automatically named layers, there is a bit more work setting up a project. However, this means that AllPlan is appropriate for mid and larger size design firms and capable of much larger projects, such as airports, whole resorts, large commercial complexes, and so on.
Solid Modeling
One of the biggest differences, though, between AllPlan and ArchiCAD is that AllPlan has an excellent 3D solid modeler directly accessible all the time, and which can even be used to carve and mold any of the architectural elements (walls, floors, roofs, etc.) at any time. Unusual roofs or warped walls, such as in the Cathedral of Ronchamps, or Saarenin's TWA building, or Kenzo Tange's arena, are a simple and easy task with AllPlan, and, more importantly, those walls or roofs would still be dynamically changeable to help find the best solution.
The solid modeler within ArchiCAD is hidden from the user. It is used internally to handle the void holes in walls, floors, and roofs, but it is only accessible through the programming language that comes with ArchiCAD called GDL (Graphic Description Language). As nice and as powerful as GDL may be, only a tiny fraction of the architects who own ArchiCAD actually study and then program in GDL to make architectural pieces. The design of sculptural elements requiring subtractive boolean operations and sweeping (special pediments, archways, fountains, wall sconces, unusual roofs, special detailing and handrails, etc.) is done by typing in numbers and programming code. The last version of ArchiCAD introduced Visual GDL as a supplemental aid, where essentially designers used the floorslab tool to fashion special parts in gingerbread house fashion then saving as GDL, which in turn wrote the GDL code automatically for you. The upcoming version of ArchiCAD improves on Visual GDL significantly. A major issue, though, is that the process results in a GDL symbol which is not as easily changeable once placed in the design as with a true 3D solid modeler.
AutoCAD
AutoCAD, as essentially a second generation 2D generic drafting program oriented to civil engineers is nowhere near in the same league or category as AllPlan or ArchiCAD. As the favorite of the largest segment of the design/CADD industry (engineers outnumber all architects and interior designers combined by more than 20 to 1) and now a required standard, AutoCAD is in a unique position, where people will adopt it even knowing it is not the best tool for their task. Like a utility truck, capable of many things, AutoCAD is really best at none, but at least usable for the largest number of people. Strangely the developers of AutoCAD seem to have rested on their laurels, particularly on many points of needed improvement important to architects, such as the need for a weld line or glue command, the need for a rectangle command where you can see the size while drawing it, the need for appropriate square foot calculation, proper metric scales (now required by all federal work), and, most importantly, a simple WALL entity upon which 3rd party developers could build a real and suitable building design program - all of which still do not exist even in the latest version of AutoCAD 13 c4.
The best thing about AutoCAD is that it has had a large enough base of users to allow the programmers to continually improve it. Whereas it was once listed as "the most user-hostile software ever written - requiring a minimum of 6 months to become productive" release 13 is a significant improvement (with lots of good ideas being transferred from the now discontinued Macintosh version). Despite Autodesk's reluctance to talk about release 14, the software still needs significant improvement, particularly since elements of both the old and the new ways of working are still within the program. New users who try to learn only the new, easier, ways, have the confused reaction that "it seems to do it differently every time" because repeating a command always reverts to the old way. Thus we have found that we really need to teach new people, both ways, not just the easier new way, increasing the training time yet again. Also, perhaps to go after much bigger markets, Autodesk is actually now trying to distance themselves somewhat from the architectural and AEC market, and leaning heavily towards the mechanical engineering market (currently dominated by CADKEY, ProEngineer, and CATIA), thus it is still unlikely that a "wall" entity - the building block of any architectural add on - will be developed any time soon.
For Architects, the best thing about ACAD13, and the main reason to upgrade, is the wonderful ACIS solid modeler. Compared to the old AME of ACAD12 (despite the fact that few people actually got it because of the extra cost) the ACIS is far faster, better, and more reliable - it is as though AutoCAD finally has real 3D. The interface on how to actually create 3D in AutoCAD has not changed, though, and, because of the difficulty of how to use it, it is still less than 5% of all the AutoCAD users out there who know 3D AutoCAD.
In reality to do architectural 3D in an AutoCAD office you need to supplement with a 3D modeler software, such as FormZ, 3D StudioMax, or Strata 3D, of which FormZ is by far the most powerful, and easy to use, which is why it is the primary modeler in use at architectural schools around the globe. The 3D Studio software is unique in its ability to do kinetic animation (where something other than the observer moves, i.e. elevators, windmills) and has good rendering abilities, but it is one of the most difficult to learn and use. After using the 3D Studio modeler, most architects end up using another modeler, even AutoCAD12, instead, and just transfer the model to 3D Studio for rendering.
For rendering, Lightscape, which runs in NT, is now the unmatched top of the field for quality and speed. Architects and interior designers who design architecturally significant places, particularly where dramatic lighting is critical, are now switching from 3D Studio to Lightscape, in dramatic numbers.
Compared to AllPlan and ArchiCAD, AutoCAD has no walls, windows, doors, furniture, roofs, contours, terrain, symbol libraries, human point perspective, easy layer-sets (except very challengly in PaperSpace), wall intersection cleanup, and certainly no architectural macros such as stairs or columns. In the past, the "best" architectural add-on package, AutoArchitect by Softdesk Inc., was too difficult, slow, kludgy, expensive, or crash prone to actually use, so most firms actually used AutoCAD vanilla out of the box. Drawing polylines, offsetting them, and then using in-house drawn block libraries of doors, windows, furniture, then trimming, and so on is still very common practice. Many offices have in-house written AutoLisp macros, which is part of the reason many feel they have too much to loose if they upgrade to even the current version of AutoCAD.
AutoCAD Compatibility
AutoCAD is a standard. No client, however, can legally require that a design firm actually use AutoCAD -- that has already been all the way to the Supreme Court and been struck down -- what they can do is require AutoCAD compatibility (which includes DXF and DWG). Now essentially all CADD programs can create a DXF file and are AutoCAD compatible (all that couldn't are no longer in business). However there are now several different levels of compatibility. Even Autodesk now makes several packages (as does Softdesk) that are only ACAD12 compatible, even though ACAD13 is the current version. Also, of the 47 architectural CADD packages by different developers, there are now 6 that have direct ACAD12 DWG read/write capability. This puts those 6 programs in a special tier of compatibility above all the rest. Both ArchiCAD and AllPlan happen to be in that special group of 6 programs that have direct DWG abilities.
AutoArchitect
Thus, though AutoCAD is, indeed a standard, and though some firms do use vanilla AutoCAD without add-ons there really is no comparison for design oriented architectural firms between the architecturally intelligent 3D design programs like AllPlan and the engineering oriented AutoCAD. A much better comparison would be between AutoArchitect by Softdesk (running on top of AutoCAD) and AllPlan and ArchiCAD. Similarly capable competitors to AutoArchitect, would be ArchT, SpeedikonA, and AP Design. At the moment, AP Design is the most comprehensive and powerful of these add-ons, followed by SpeedikonA (the adaptation of the excellent Microstation add-on), then AutoArchitect, and then ArchT. However, ArchT is gaining the most market right now, since it is simpler, easier, faster, cheaper, far more stable, and actually better at 3D and automatically generating elevations and sections than the others. These add-ons are covered in more detail in our other reviews - for the comparisons here though it is sufficient to deal with them together.
Combined with any of these higher level architectural add-ons to AutoCAD13, with the ACIS 3D solid modeler, and, perhaps a renderer such as 3D Studio, Accurender, or Lightscape you would indeed have a powerful combination. Conceptually, Autodesk (and the Microstation people say the same thing) argues that the best solution to the AEC design needs area is a generic "engine" with various 3rd party add-ons for specific applications - that the "one building database" would remain somewhere on your network and each engineering or design discipline could call up those common reference drawings and edit with their own add-on. This line is great for executives who do not actually use this technology to say; unfortunately the reality is far from that simplistic dream. A jack of all trades is master of none - a phrase thousands of years old - is quite apropos here. For a carpenter a real hammer is far better than one of those all-in-one kit tools. Hampering your design team with a slow, kludgy, crash prone system that does not even allow them to design certain types of things is not a great solution. Also, for Autodesk, now relying on another company, Spatial Technologies Inc., to make the needed improvements to the ACIS 3D modeler is another problem. For architects, having to combine, yet another (AutoArchitect) and possibly others (for symbol libraries, utilities, viewers, and so on) slows the system down more and more, makes it less reliable, and requires more training time on the various manufacturers programs.
At the moment, all the add-ons actually still use AutoCAD's ridiculous 2.5D of extruded lines (thickness) and then band-aid over the tops and bottoms of windows and doors with patches of 3D faces (the old AutoCAD 10 technique from 1987) and then hide the edges (try turning the edge display on and you will see) in order to have the image look right. This patching process results in "models" that cannot perform true solid modeling on the design (limiting design ability) and certainly take longer to render. Even if the files are exported to 3D Studio, the translator actually just creates thousands of triangulated flat 3D faces (destroying the integrity and look of curved arches). Strangely, even though real solid modeling is part of AutoCAD now due to ACIS, none of the add-on products make use of it (or create a de-facto wall entity). This, hopefully, and probably, will change over time (perhaps Autodesk's alliance with Spatial Technologies was too soon before the release of ACAD13 to allow the third party developers the ability to work with ACIS. The problem is that AutoCAD is not a finished or ready product from an architectural design point of view - not ready for prime time - and Autodesk is mum about any AutoCAD14 that may or may not appear in 1997.
A far better product, in the same genre, is the Bentley brother's Microstation product, with it's more powerful add-ons such as Triforma, Speedikon, Brickworks, and MicroArchitect (in that order). Strangely, though, they charge over $1000 more for the ACIS solid modeler, the same one that AutoCAD includes free (though Microstation has a better 3D interface to it), so that their 3rd party developers cannot assume the ACIS is there to work with. Also, Bentley has been working on (and announcing) a new development for years now called Objective Microstation, essentially a modularly programmed version that gives third party programmers better control over the drawing file database as well as easier development tools. Every one of those developers claims that their product will be the absolute best once this new thing is implemented. As everyone who has waited for DataCAD for Windows knows, however, you cannot wait for the promises of CADD software developers. As with the case of AutoCAD add-ons, although Microstation is better (as number 2 they have to try harder !), the concept of add ons itself suffers in reality.
An interesting development is the announcement this week by Nemetschek Systems Inc., about a potential development of AllPlan running on top of Microstation. They do this for marketing reasons, and are smart to do so, despite the limitations of add-on software and the fact that you shouldn't expect such a product before 1998.
A number of very large architectural design firms have only recently made the switch from first generation to second generation CADD software, at great expense, and are not likely to switch again to third generation software for quite some time. Among these firms are Sheply Bullfinch (Arris to Microstation), SOM (IBM AES to AutoCAD), RTKL, Einehorne-Yaffee-Prescott, Tsoi-Kobus, and many others. These firms all use an older business model of separate designers and drafting departments with back and forth redlining systems. For these, and other large AE firms who essentially generate paper documentation of collaborated work of many design and engineering disciplines, the second generation CADD software using various add-ons is probably appropriate. These firms will miss, however, the tremendous opportunities afforded by the integrated architecturally intelligent 3D project third generation software - where the decision making designer has the information and power at their fingertips, so they can concentrate on the design of 3D spaces, not on the mechanics of drafting plan-smiths.
Synopsis of Strong and Weak Points
AllPlan - architectural - better at 2D drafting and 3D modeling than ArchiCAD - best for most mid size and larger design oriented arch firms - allows for collaboration across a network - although everything else changes parametrically, walls cannot change width automatically - best roof design abilities in the entire industry - stunning dynamic rendered virtual reality visualization mode (called "animate")
ArchiCAD - architectural - simple and easy to use - difficult to coordinate collaboration - no reference files - best for sole practitioners and very small firms - automatic layers - excellent way of handling symbols - automatic fast easy walk through animation
AutoCAD - 3D ACIS modeling r13 output to 3DS is faces ala r12 only - best for civil engineers and large AE firms - allows for collaboration across a network - AutoArchitect, ArchT, Speedikon, AP Design, 3D Studio needed to do architecture - allows for saved views with layer sets (in PaperSpace) - with overlays by other companies becomes very slow and unstable (crashes) - many 3rd party add-ons available for different tasks
Geoffrey Moore Langdon, AIA Architectural CADD Consultants http://www.architecturalcadd.com
June 26, 1996