BIM and too much detail

[KeesW]

We do a lot of small and medium sized work and have too many drawings for each project. I wonder if the use of BIM causes this because everything has to be resolved to produce a good model. Then, if it is resolved, one might as well include it in the documentation. This leaves too little to the contractor's discretion, and the amount of detail provided makes him think that the works are more complicated than they are. This increases the cost.

An independent technician working from our office, using Microstation as a 2D drafting tool, produces full working drawings for small projects such as houses in a few days. Of course, things are not as well resolved but information is more than adequate for contruction purposes, and the quotes he gets from contractors are much lower than ours for similar sized projects.

I understand that resolution of every miniscule item might be necessary for large developer driven projects where profit and avoidance of liabilty are the main considerations. However, for small and medium jobs ........?

Any opinions on this?

[Arcadia]

but at this point it looks like the extra hours spent on the model are more than made up by a combination of getting a lot of sections and plans quickly

I agree with this. And I find the more complex the job is the better the payoff and time saving from doing a proper well detailed model. In terms of time spent I find that for really basic residential jobs AC is only fractionally quicker to complete a job than 2D drafting (although still providing a better quality documentation for this time) but the larger/more complex the job is the more time you save over a 2D workflow.

[Link]

IMHO deciding how far to model is a balance of knowledge, time, organization, information, hardware/software capabilities, and industry expectations.

In our office, For complex projects (eg. multi residential, high rise, etc.) we have a sweeping rule to model to 1:50 scale (1/4" for the imperialists). That is to say that if you can't make out what it is on a 1:50 scale drawing then don't model it.

The benefits of this are:

>Anyone in the office can model to 1:50, then further detail can be added in 2D by the more experienced documenters.

>Time is not wasted modeling small elements that won't be seen in all views.

> Teams can be organized according to this level of detail.

>Enough information is provided to construct the building with minimal RFIs and errors.

>The file size does not blow out due to excessive polygons and information, making teamwork, hotlinking and layout books more manageable. And it's not too much of a strain on our client machines which are all currently quad core, 64 bit, 6Gb RAM PCs.

I would love to see this sweeping rule dropped to a 1:20 scale, but I know it will take time to educate staff, improve processes, upgrade hardware, improve libraries, and most importantly wait for ArchiCAD, IFC & the industry to mature.

Because no longer is it just about getting the information onto drawings, but modeling everything so it is accounted for in the Building Information Model.

If we could apply tags and parameters to all 2D & 3D elements in ArchiCAD and share all of it easily with other consultants, then it will become more urgent to model to a finer detail.

Until then do what suits your balance.

Cheers,
Link.

[David Maudlin]

Arcadia wrote:
In terms of time spent I find that for really basic residential jobs AC is only fractionally quicker to complete a job than 2D drafting (although still providing a better quality documentation for this time)...

True, except you are also getting the 3D model for presentations, comprehension of the design, construction conflicts, etc. Plus, revisions are more efficient.

David

[Erika Epstein]

Link wrote:
IMHO deciding how far to model is a balance of knowledge, time, organization, information, hardware/software capabilities, and industry expectations.

In our office, For complex projects (eg. multi residential, high rise, etc.) we have a sweeping rule to model to 1:50 scale (1/4" for the imperialists). That is to say that if you can't make out what it is on a 1:50 scale drawing then don't model it.

The benefits of this are:

>Anyone in the office can model to 1:50, then further detail can be added in 2D by the more experienced documenters.

>Time is not wasted modeling small elements that won't be seen in all views.

> Teams can be organized according to this level of detail.

>Enough information is provided to construct the building with minimal RFIs and errors.

>The file size does not blow out due to excessive polygons and information, making teamwork, hotlinking and layout books more manageable. And it's not too much of a strain on our client machines which are all currently quad core, 64 bit, 6Gb RAM PCs.

I would love to see this sweeping rule dropped to a 1:20 scale, but I know it will take time to educate staff, improve processes, upgrade hardware, improve libraries, and most importantly wait for ArchiCAD, IFC & the industry to mature.

Because no longer is it just amount getting the information onto drawings, but modeling everything so it is accounted for in the Building Information Model.

If we could apply tags and parameters to all 2D & 3D elements in ArchiCAD and share all of it easily with other consultants, then it will become more urgent to model to a finer detail.

Until then do what suits your balance.

Cheers,
Link.

I agree; Very well stated Link.