Showing posts with label Estimating. Show all posts
Showing posts with label Estimating. Show all posts

#Revit 2012: Using the Create Parts feature for Quantity Take-Off

I am a bit disappointed with the new Create parts feature, let me tell you why.
Català - Castellano - Deutsch
I was very excited about the new Create Parts feature for Revit 2012. I thought it would simplify a lot the process of extracting quantities from a Revit model, by allowing to play with the different layers of a wall or floor (as other BIM packages like Allplan allow). yesterday I gave you the link to the video explaining the features.

My disappointment came today, when I realized that whatever you modify using the Create Parts feature, doesn't get reflected in a default Material Take Off Schedule. My first thought was the following:
"I tried it, it simply doesn't do anything. So as far as i understand it, the Create Parts feature is just a tool for representation. This to me is the wrong approach to go Autodesk. Revit (and BIM) is not just for representation, if you can't get accurate Quantity Take-Offs and thus accurate estimates from a model, what is the point of BIM?"
But then I thought, this can't be it, such a cool feature can't end on a mere representation of parts. So I dug deeper and found that you can use it for Quantity Take-Off.

The key is that you need to create a Material Take-Off specific to list the parts, and you do it like this:
  1. Click View tab > Create panel > Schedule > Schedule/Quantities. Under Category, select “Part”
  2. Then add the categories you need for your take off, like Material: Name, Material: Area, Material: Volume, etc
It works, and it is great.

I am starting to realize as I read on this post, that REVIT CAN DO EVERYTUIN. Well not yet, but it is getting there, and this post and my chain OF thoughts should serve as an example of how sometimes we blame the Software (and the SOftware designers) for our own lack of expertise with it.

There is just one little BUT I haven't been able to solve. Using Parts combined with Groups doesn't seem to work well. After I created my Bathroom (the one on the first picture) I needed to copy that group all over the buidling since it repeats many times. When I used "Create Similar", the newly create Group, has all the parts reset to default. If you copy the group directly, it does work better, but in my example, some of the parts got reset as well to default.

Need to find out about this point if it is my fault or Revit's fault. So far it seems to be Revit's fault, since I am allowed to modify parts of elements that are inside groups without entering the edit gropu mode, and those changes are not reflected to other instances of the group. A little bug, hopefully it will be solved on Revit 2013.

BTW, I found the solution again via RevitWikiHelp, awesome database of solutions.

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Revit: Calculating the weight of structural members (and how to Fix that "Inconsistent Units" Problem)

Calculated values give sometimes "inconsistent units" errors. there is a fix for that of course.
Català - Castellano - Deutsch
I recently blogged about using Revit for Quantity Take Off. One of the things I was mentioning was the need to obtain the total steel weight to be able to estimate the costs of a steel structure. This is how I did it.

The main idea was to obtain the weight of the steel members. I will use the beams and bracing elements schedule for this example. I had families for the structural members with a weight per lineal meter parameter in them (I introduced that parameter myself from steel catalogs). I still needed to get Revit to calculate the total weight of each element with a fórmula. To do that, we need to add a new column on the schedule with a calculated value (length of the structural element times the weight per linear meter). On the Schedule view, click the Edit button near the "Fields" text in the properties palette. Then you will get a dialog like the one below (I am assuming you already have created a Schedule for Structural Beams and Bracing, and added the W parameter were you have entered the Weight per Linear Meter for each type of structural member).

The value we want is a calculated value of the default Length parameter times the W parameter we have created (Weight per linear meter). So we click on Calculated Value and we get the following dialog.

Logic seems to ask for a simple formula like "Length * W", but if we use this formula, we will get an error saying "Inconsistent Units". Well, this point turned me crazy for some hours until I found a solution here. Apparently, since Length has meters as units, you can't get a calculated value unless you "neutralize" those units. The formula in this case to be able to get the calculated value is "Length / 1 m * W". By dividing Length by 1 m, we eliminate the units from the formula and we are able to obtain the much wanted total weight for each element.

After doing this, my structural elements schedule looked like this, ready to be exported with all the information I needed to be able to do some estimations on the building structure (the right colored column shows the weight of each structural member).

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Vico Software: BIM Master Series

Interested in BIM for Construction Management? The Vico BIM Master Series might be a good place to start.
Català - Castellano - Deutsch
I think out of all vendors pushing for BIM, Vico Software is the one with more knowledge and development in the area of Construction Management.

They have a great series of Webinars about Building Information Modeling (BIM) related to Construction (Scheduling, Estimations, Quantity Take-Offs, etc...). I will just post the links here for you to easily access them:

  • BIM 101: An introduction to BIM and some of its dimensions (3D, 4D, 5D)
  • BIM 201: How to use BIM during preconstruction, Integrated Project Delivery and some issues related to contracts between stakeholders
  • BIM 301: All about contracts related to BIM.
  • BIM 401: Scheduling with BIM and Flowline, learn about Location Breakdown Structure, Vico Control, etc.
  • BIM 501: Do you want to get estimates from your BIM model? Do you want to use the Quantity Take-Off from the BIM to plan and control production? This is your webinar then.
  • BIM 502: Learn about conceptual estimates and differnet modules of Vico Office.
  • BIM for Executies: All Managers need to know about BIM, costs, ROI, what BIM does, etc
A great way to learn about BIM for Construction. If you don't have time for the webinars, maybe you want to check the BIM Glossary the have posted here.

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First Thoughts on Using Revit for Quantity Take-Off

Some thoughts, doubts, suggestions and questions after using Revit to help on a project quantity take-off process.
Català - Castellano - Deutsch

I've been working for the past month and half (really 3-4 weeks if we don't count the Christmas break) building a Revit model of a residential project in Barcelona. The model is being used in a pilot project to extract quantities, check for undefined elements and of course help visualize the building. The initial aim was to be able to do a complete quantity take-off from the Revit model, based on the drawings already finished (finished is a very optimistic term here...) by the architect.

I just wanted to share some thoughts I've been having the past weeks about the workflow and problems I encountered so if you are doing something similar either you ca give me some feedback or avoid doing the same mistakes as I have.

To put this in perspective, all this process has been done trying to follow certain Spanish (or Catalan) standards. I really don't know how you guys do estimations in other countries, what I explain here will be based on the way we do, or we try to do certain things.

Let me be more concise and put an example. The first time I showed someone the Schedule of Structural Beams, everything was WAWS and OOOH!. Soon I realized though, that the amazing automatic schedule that Revit was providing was:
A) Not showing the Steel Weight (which is the standard way to do Take-offs here when describing Steel Members and
B) Not splitting the Elements by Floor in the schedule (which is also very necessary in case some cost analysis needs to be run, to be able to say for instance "if we reduce one level, we would have this less steel")

The way I went around point B, was using Phases. I Created a Phase for each level and moved all Columns and Beams of each level to the corresponding Phase (20 minute work, no big deal). This way, I could visualise the schedule using Revit Phases, and could export the quantities for each level separately (showing the phase as a property in the schedule is still something I am trying to figure out how to do...any ideas?).

Point A was a bit trickier, so I will write a second post about it soon to not bore you all with so much text. I will also post soon about an Allplan 2011 demo I went recently, and my first thoughts on how Allplan related to Revit, what is better, what is worse, etc.

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