Have you ever wondered what it takes to complete the Scan to CAD process? How much time will you will spend to get the result you want? Is it as simple as everyone claims? Let’s break down what it takes to finish a 2D drawing.
First let’s start from why new users often thinks that once a scan process is done, the remaining part of data registration and modeling will be easy and almost automatic.
For those who are new to 3D survey scanning all the automatic modeling features might look attractive, but experienced users will know right away if something like this will actually work or not.
An opinion like this is often formed by those who do not have any real modeling experience, while modeling with any software will be easy and almost automatic.
Is it true? Well yes and no. Theoretically speaking most of the software options have automatic modeling functions which will allow you to recognize planes, generate lines in between and so on. But right now there is no such software which will do everything faster and more precisely than an experienced user. In our opinion we will have to wait quite some time until such a solution is available. So let’s take a look at what it really takes to make a 2D drawing from point clouds data, and how you can make it super-smooth
The first step is to register scan data into a project. Creating a correct point cloud project is really important because it will be used during the entire modeling process. And, this is where you can really start saving time. We compared project creation time between Autodesk ReCap and Undet Indexer. While everyone who works with point clouds knows about ReCap, Undet Indexer might be something that you have not heard of before. Undet indexer is free standalone software to import your point cloud files into the UNDET database. You can read more about Undet Indexer here.
We compared the project creation speed between ReCap and Undet Indexer, and the creation times with Undet Indexer were 3-7 times faster than Autodesk ReCap software, based on testing performed (Undet Indexer vs. Autodesk ReCap) | comparison video.
Once you have created a Point cloud project you will use the Undet for AutoCAD plugin to load it into the AutoCAD environment. Once the project is loaded the Project tab will be filled with all sorts of information about the project which will be visible until you close the loaded project.
2D building modeling can be separated into 3 drawings: building elevation, building section and floor plan. Even though a floor plan drawing work flow is slightly different from section and elevation drawing work we will talk about them all at once since the outcome and the target are the same- to draw elements that can be seen in that specific plane.
We created the Undet plug in with our development team according to user needs. So that people will be able to use our software on their preferred CAD software, and with that being said it is safe to say that this plugin was created to improve the user modeling time without changing modeling habits.
The first step of our suggested super-smooth workflow is to create a correct UCS. You should find the longest building wall and rotate the view by drawing line and using the command view by line from the visibility management tools tab. After this you can create a new UCS that is defined by the current view. At this point you should save the new UCS using the UCSMAN command from the command line. We recommend saving a UCS every time you create a new one.
To make sure that your new UCS is correct, you should draw some perpendicular lines to see if these are parallel with the building walls. You should draw multiple lines and check a couple different walls.
The second step is to create the view section of your area of interest. Here Undet becomes handy once again. Creating and managing view sections in Undet is much easier than performing the same actions with crop areas in the native AutoCAD environment. Every time you create a new view section it will be automatically saved in the view section list. We also created keyboard shortcuts for current view section selection- Ctrl+Shiht+Q and view section grip switching- Ctrl+Shift+1. You can find out more about view section clipping box management here. We recommend creating multiple view sections in the beginning: one for floor view, one for ceiling view, one for section view, etc.
The third step is the main outline drawing. It does not matter if you are working with a section or floor plan drawing, once you have your UCS and view section ready for modeling, you should start from the main outlines.
View section of external walls with isolated external scan data.
External walls modeled according to point cloud information.
The forth step is internal wall drawing. This step is almost the same as the previous one, except the fact that now internal scans data will be active in the view section. Once again, by using the UCS that you created you should be able to model walls which will be parallel and perpendicular to each other as long as there are defined tolerance boundaries. Depending on your project, our specialists suggest using 30 mm tolerance.
View section of internal and external walls.
Internal walls modeled according to point cloud information.
The fifth step is wall element drawing. To simplify, in this step you should draw doors and windows. Using Undet dynamic blocks this step becomes really easy, because you can add doors and windows of any size and orientation by adding the same block everywhere and adjusting the size and orientation using interactive grips.
View section of windows and doors.
Windows and doors added using dynamic blocks according to point cloud information.
Detailed view of window profile.
The sixth step will be floor element drawing. In this step you will create a view section in which you will be able to see all floor elements such as stairs, radiators, bathroom and kitchen fittings, furniture and so on. Once again dynamic blocks will be handy. If you are working with elevation drawings in this step you should draw additional facade elements.
View section of additional floor elements.
Additional floor elements modeled and added using dynamic blocks according to point cloud information.
The seventh step will be ceiling element drawing. In this step you will create a view section in which you will be able to see all ceiling elements such as sloping ceilings, changes in ceilings, soffits, beams and so on.
In this step we recommend working on one room at the time, because ceiling level values might be different in each room, and if you work with one big view section you might miss some elements.
This step should also include roof element modeling.
View section of ceiling elements.
Ceiling elements modeled according to point cloud information.
The last step will be drawing annotation. This step will be a little bit more complex, because you will have to add different annotations to different objects. Undet also provides dynamic annotations, which will help to save you a lot of time. In this step creating the correctly sized view section will save you a lot of time, because you will be able to move it to different locations and reuse the same one instead of creating a new view section all the time. Annotation value adjusting using multiple view ports is a must while working with annotations, because it saves a lot of time compared to how long it takes to add annotations while using the single view port.
In elevation drawing this step should be the same.
View section of ceiling elements.
Final floor plan drawing completed according to point cloud information.
Annotation value adjustment using multiple view ports and dynamic annotation blocks.
As you can see, modeling might be challenging, but if you use our suggested workflow the process of making complete 2D drawings will become super-smooth and easy.
Undet for AutoCAD | How to start- https://youtu.be/CxQnOqjPRYQ
Undet for AutoCAD | Building elevation drawings from point clouds- https://youtu.be/RftPM1IKoLA
Undet for AutoCAD | Floor plan drawing from point clouds- https://youtu.be/BxWeAv5rr5Q