06:02
Hello everybody! I know it has been a while since my last post. I’ve been busy writing an article for AUGI AEC Edge magazine which is slated for inclusion on its upcoming Fall issue (to be released sometime in December 2010). In the article, I’ll be presenting a lot of practical tips and tricks in Revit family modeling. You don’t want to miss this issue. I’ll be including a few instructional videos as well as a couple of free downloads.
For today’s post, we will be looking into Autodesk Inventor 2011 as a source of Revit content. As you may know, I’m a staunch supporter of families created in native Revit geometry. However, there are some complex shapes that are extremely difficult or impossible to create using the Family editor tools. Just recently, I created a model of an electric guitar. I wanted to produce a unique Revit family where I can get to use all the tools in the family editor. Please check it out at:
Although I am very pleased with the outcome, I wasn’t able to model it exactly as I had planned to. I wanted an arched top to go along with the smooth body profile. The concept is easy enough to execute by using an arch void extrusion applied to the top of the guitar body. The problem is I could not round the edges. Revit does not allow you to do a void sweep on edges created by a void and solid extrusion (see Figure 1):
Figure 1
After a few failed attempts, I abandoned the idea of an arched top in favor of a flat top. I then decided to take a closer look at other 3D applications to see if I can create the guitar design I had envisioned. This is when I discovered Autodesk Inventor 2011. Before I explain how I got into it, take a look at how easily Autodesk Inventor created the arched top as shown in Figure 2. The top curve is also tangent to the rounded edges.
Figure 2
Introduction
Although most content can be created with the Revit family editor, there are exceptions. Among them are highly complex families and propriety equipment from specialty manufacturers.In creating an arched-top guitar with smooth edges, I looked into 3ds Max, SolidWorks, Rhino, Alias and Autodesk Inventor. I wanted to find a flexible 3D modeling software that can be used in design and documentation of complex geometries. After seeing demos of these applications, I kept coming back to Autodesk Inventor for its intuitiveness and ease of use. I eventually chose it and spent two weeks learning and experimenting on the modeling tools. On the third week, I started creating the guitar. I knew it was an ambitious project for a software I wasn’t experienced in. After a lot of trials and errors, I got the guitar to its final incarnation.
The intent of this article is to show you an alternate software we can use to create complex shapes. Although the Family editor does a good job of replicating complex forms, it lacks the tools to create organic shapes. However, Autodesk had made a huge leap by incorporating the powerful massing tools we now use in our project environment. In time, I believe the Family editor will evolve into a very powerful content generator. For now, we can supplement Revit with Autodesk Inventor. Here are some of its advantages:
- Inventor is able to create accurate complex models that can turned into a digital prototype.
- It can open Revit files
- It has native translators for exchanging data with other 3D manufacturing software such as Catia, SolidWorks and Pro/ENGINEER.
- Inventor files can be imported into Revit Architecture and Revit MEP using the Autodesk Package Files Format (.adsk).
- Autodesk Alias Design has a plugin for Inventor (Autodesk Alias Design for Inventor). This adds powerful NURBS capability to inventor, thus allowing free-form shape modeling.
NURBS stands for Non-Uniform Rational Basis Spline. They are mathematical representations of 3D geometry. They are used in computer graphics for generating and representing curves and surfaces. NURBS was developed in the 1950s by engineers who needed accurate mathematical representation of freeform surfaces such as those found in cars.
I would like to mention before I go on that this is not a review of Autodesk Inventor. It is about my first impressions of the software from an architectural Revit modeler point of view. My focus will be on its powerful modeling tools that Revit Architecture users need to know.Autodesk Inventor in a nutshell
Autodesk Inventor is a 3D mechanical solid modeling software used in the manufacturing industry. It is used for designing and creating 3D digital prototypes of products. With these prototypes, you can predict how a design will work under real-world conditions before building it. The need for physical prototypes can be eliminated, thus minimizing manufacturing costs. You can also do stress analysis of parts and simulate motion. Other uses are:- tube and pipe design
- cable and harness design
- tooling and mold design
- 3d layout and system design
- Plastic part design
- sheet metal design
- assembly design
http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=13769393
http://www.highbeam.com/doc/1G1-78781704.html
http://www.evansonline.com/
To show you how some of the tools in Inventor work, I’m going to use the red guitar as an example.http://www.highbeam.com/doc/1G1-78781704.html
http://www.evansonline.com/
The Autodesk Inventor Modeling Tools
1. The learning curve, Interface and Work Planes:
Every 3D program has similar tools and only differ in their execution approaches. If you’re an experienced Revit modeler and well versed with other 3D programs, you’ll be up and running in an hour! If you’re a beginner, the modeling tools are easy to learn after you understand the concepts and go through some tutorials. Of course it takes a lot of practice to get to a level when you can start modeling real life objects.Revit users will be at home with this software. Inventor is sketch based! Inventor also adapts the Ribbon interface and the Quick Access Toolbar (QAT). Like I’ve done in my Revit setup, I relocated the QAT below the ribbon. Here is a snapshot of its Model tab:
Figure 3
When you start a new model, by default you are taken to a Sketch mode of a Part file (more about this later on) as shown in Figure 4. You’ll be in a view parallel to the XY work plane. This is the right orientation if you want to export your file to Revit. In this orientation, the View Cube will show that you’re in the Front view. In Revit, the View Cube will say Top.
You can change the start-up action by going to Tools>Options>Application Options>General. This is if you want a different template to open up or if you want to choose a file from a menu.
Figure 4
In Inventor, there are no plan and elevation views. You go to these views through the View Cube. You can also create multiple 3D views and organize them in your screen. Take a look at its numerous view options (Figure 5):
Figure 5
2. Starting an Inventor Model
There are four file types that can be opened when you click the sub menu (triangular arrow) next to the New icon from the QAT. They are Assembly, Drawing, Part and Presentation (Figure 6). You’ll do most of your work in a Part file.
Figure 6
To give you an idea of how these four file types differ, take a look at the red guitar assembly (Figure 7).
Figure 7
Each label points to a Part. Each part can consist of many components. All these parts combine to form an Assembly (the guitar as a whole). To document each part or assemblies, they go into a Drawing file where they are labeled and annotated (pretty much like the Revit sheets). The Drawing file also includes the Bill of Materials and exploded views. The Presentation file are renderings, walkthroughs and animation that is used to help clients visualize the product. This is done through Inventor Studio, Inventor’s built-in renderer and animation generator (Figure 8).
Figure 8
3. The Sketch Tab
After you select a plane and click New Sketch, you’ll be presented with a view parallel to the plane you’re going to be working on (you can also choose to sketch on an isometric view). Here is what the Sketch tab looks like (Figure 9):
Figure 9
You’ll notice familiar tools in the Draw and Modify panels. Images can be imported in the Sketch mode through the Insert panel. For the body of the red guitar, I traced a standard guitar shape from a cut sheet image and based my design on it. Here is my final sketch (Figure 10):
Figure 10
In the image above, you’ll notice a palette on the left side (A, Figure 10) that looks like the Revit project browser. Inventor calls this Browser Pane. In a Part file, it list all the files and features used. These features are the extrusions and every transformation applied to the part. The background in the modeling area (B, Figure 10) can be customized in different ways from the Application Options (Tools>Options).
4. The Extrude Tool
When you’re done sketching, you click Finish Sketch located on the far right of the ribbon (the panel with the big green check mark). The sketch animates into a 3D isometric view. You then click on the Extrude command (Model>Create). A preview of the extrusion (A, Figure 11) with a preset thickness of 1″ will emanate from the sketch. You then specify your thickness and choose other options available in the Extrude dialog box (B, Figure 11).
Figure 11
The cluster of small icons in C (Figure 11) is a direct manipulation mini-toolbar. Basically, it’s a compact version of the Extrude tool’s dialog box. You’ll notice this in some other form when you click other commands after finishing a sketch. They will pop up in close proximity to the object you’re working on. When you’re not in a command and you click an edge or surface, it appears to give you quick access to editing options. The advantage of course is that there’s less mousing around to find the options you need. There’s also the Manipulator arrow (D, Figure 11). This allows you to interactively drag the arrow till you find the thickness you want.
5. Using the Extrude Tool to Cut a Component
To create the arched top, I went to a side view plane and sketched this shape (Figure 12):
Figure 12
After clicking Finish, I clicked on the Extrude tool (selecting the Cut option) and dragged the Manipulator arrow till it covered the top of the guitar extrusion (A, Figure 13). The resulting shape is shown on B (Figure 13):
Figure 13
6. The Fillet Tool
To create the round edges tangent to the arch, I clicked at a line from the edge of the body (A, Figure 14), chose Fillet from the mini-toolbar and applied a radius of 1/4″ (B, Figure 14):
Figure 14
In the image above, you’ll notice a label named Select Other (A, Figure 14). This is another mini-toolbar that pops up (after a user specified time) when you click a line or surface. It’s Inventor’s way of selecting other lines or faces that is obscured by an object. Clicking on the forward or backward arrows cycles and highlights the object you want to select. Once you’re on the particular object you’re looking for, you click the rectangular box in the middle of the two arrows to select it. Here is the smoothened body (Figure 15):
Figure 15
7. The Revolve Tool
Just like in Revit, you just draw half of the profile of your component. After clicking Finish, you select the Revolve tool. You will then be prompted to select the profile and the axis in the Revolve dialog box (A, Figure 16). The component shown on B (Figure 16) is a part of the tuning keys assembly. It is the post where the string is wound to. The hole on the post was created with a cut extrusion. Pretty straightforward.
Figure 16
8. The Loft Tool
This a powerful tool that lets you create complex and organic shapes. Think appliances and cars! It can combine multiple profiles in different planes and transform shapes between these profiles very smoothly. I’ve only used it for the neck parts (Figure 17) of the red guitar so I don’t have any more samples to demonstrate its awesome capabilities.
Figure 17
Please check out this link to learn more of the Loft tool’s power:
9. The Sweep Tool
To create a sweep, you draw a path and a profile. You then click the sweep command which basically extrudes the profile along the path you’ve drawn. In Inventor, you can have more than one profile as long as they’re in the same sketch. You can also have a path and a guide rail. To explain what a guide rail is, think of a hair dryer handle. One side is curved. This would be the path. The opposite side has smooth ridges to conform to our hand grip. These smooth ridges is the guide rail. I used the Sweep tool to create the strings on the red guitar (Figure 18).
Figure 18
10. Inventor Visual Styles
In Autodesk Inventor, you have a choice of ten visual styles (yes_10!): Here they are (Figure 19-23):
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
I wish we had all these styles in Revit!
11. Inventor Studio
Inventor Studio is the rendering environment within Autodesk Inventor. It is based on the mental ray rendering engine. With it, you can create high-quality photorealistic renderings and animations of your model. Inventor also utilizes Styles. Styles are basically preconfigured specific settings of lights, render scenes and backgrounds. Or you can create your own setting and save it as a style. This is an excellent feature that makes rendering an easy task to accomplish. Here are two examples showing Lighting and Scene styles (Figure 24):
Figure 24
Here is a rendering based on one of the Styles (Figure 25):
Figure 25
Like Revit, Autodesk Inventor is another application that uses the teapot icon to signify stuff related to rendering (Figure 26).
Figure 26
If you want to know the significance of the teapot icon, go to:
12. The Red Guitar Imported into Revit
Here it is (Figure 27)!I had to make a couple of adjustments to the materials but basically, Revit imported all the geometry from Inventor!
Figure 27
Now for the information you want to know, here are the pros and cons of using an Inventor generated content:
Pros:
- The Inventor file imported into Revit is significantly smaller in file size than the guitar created with the Revit family editor (Inventor: 2,737 KB; Revit: 3,767 KB).
Note: The 2,737 KB file was a straight export from Inventor. Inventor utilizes a method to make a model compact called Shrinkwrap. Basically, this is reducing the level of detail of an assembly to improve computer performance. This is done by suppressing or removing features, combining parts so they behave as one, representing certain parts as hatches, etc. The shrinkwrapped .adsk version of the guitar got down to 1,560 KB!
- Saved as an .adsk file, information about the Inventor model is retained in Revit (see Figure 28). Thus, you can schedule this equipment.
Figure 28
- You can create extremely complex shapes for use in the Revit project or family environment
- You get accurate representations of models
- Materials and material names are retained in Revit. Yes, you can change Inventor’s material finishes in Revit!
- You cannot edit the geometry of an Inventor file in Revit
- Custom tweaks of materials done in Inventor don’t transfer to Revit. For example: when you’re in Inventor and you use a different jpeg to represent a standard Inventor material, it does not transfer into Revit, even if you use the same jpeg. The work around here is to specify a different material in Revit.
Revit has a limitation on how small you can draw lines or hatches. When you draw anything smaller than 1/32″, you get an error message. When it encounters imported geometry whose size falls below this limit, it does not display it in Realistic or Render views. If you go back to Figure 27, you’ll notice there are only 5 strings in the guitar. That’s because the sixth string is 0.010 inch in diameter. The only way to see it is when you’re in Wireframe or Shaded with Edges views.
Revit was not designed for modeling small circular objects. When you do so and it falls below a certain threshold, it display it as faceted. It does this for imported files too.
Conclusion:
I’ve only scratched the surface of this powerful software. I know I left out a lot of things but please understand that I’ve only used it for three weeks. To explain a feature or tool which I have not used extensively would be unfair. For now, I know I can rely on Inventor to create extremely complex geometries. If you get into it, I would urge you to understand the part/assembly workflow. It is different than what we’re used to in Revit. Bear in mind that Inventor was developed with manufacturing and digital prototyping in mind. And so to be effective, you have to adhere to certain steps and measures to make your model solid and stable.Aside from this, the modeling tools are so intuitive. You will love the total experience when you’re inside the program. Objects are displayed magnificently even when you’re modeling extremely small objects. The mini-toolbar concept is an awesome feature. There is more than one way to customize the color combination of your graphics window. Then there’s the various visual and render styles.
Thanks for taking the time to read this article. It’s up to you now to test drive Autodesk Inventor.
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