3D Modeling & CAD for Motorsport: Datums
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Datums
07.02
| 00:00 | - In this module, we'll get stuck into learning the basic tools that form the fundamentals of modelling in CAD software. |
| 00:06 | More specifically, solid modelling with the intent of creating 3D solid designs. |
| 00:11 | Some of these tools are also used in modelling of sheet metal parts and building assemblies which we're going to be covering a little later in the course. |
| 00:20 | To start things off, let's discuss datums and how to create them and use them. |
| 00:25 | Datums are imaginary reference features, generally used for the construction of a model but can also be used for other tasks like measuring and creating section views for drawings. |
| 00:35 | These come in three main forms, planes, axes and points. |
| 00:39 | You can think of them as the foundations of your model, from which everything else is built on. |
| 00:45 | Let's head over to Fusion360 to get a better understanding. |
| 00:48 | Now you might remember that we touched on the coordinate system in the getting started module. |
| 00:53 | This system represents the default datum features that are used to construct our model and is made up of 3 planes, axes and a point. |
| 01:00 | Making sure our origin is visible up here in the browser, we can now see our default planes, axes and origin point in the model space. |
| 01:08 | Here we have our three planes, top, front and right. |
| 01:12 | Our origin point is at the intersection of these three planes and then we have our three axes. |
| 01:18 | Y axis runs along the intersection of the right and front planes, X axis runs along the intersection of the top and front planes and the Z axis naturally runs along the intersection of the top and right planes. |
| 01:32 | Because of this, it's also common for our top front and right planes to be referred to as the XZ, XY and YZ planes. |
| 01:40 | While these default datum features are very useful, we can also create new datums. |
| 01:45 | Making sure we're in the design workspace under the solid toolbar, we can create new datums using the construct tool. |
| 01:52 | Under the dropdown menu here we have a list of different methods for creating construction planes, axes and points. |
| 01:59 | What features we have available to us will determine the best method to create the datum but the final planes, axis or point will function the same regardless. |
| 02:07 | Let's start at the top of the list with the most straightforward, an offset plane. |
| 02:11 | This simply creates a plane parallel to the reference which could be another plane or flat surface but at an offset distance. |
| 02:18 | We'll give this a go now by selecting the plane that the new constructed plane will be offset from. |
| 02:23 | Let's go with the right plane here and then we can either click the arrow to drag the new plane which will increase the offset in increments of 5 mm or set the distance to whatever we need. |
| 02:34 | Let's say 35 mm for example. |
| 02:37 | Hit OK and now you can see that we have our first constructed plane. |
| 02:41 | Looking at the browser, we now have this construction tab which contains the new plane. |
| 02:45 | Remember we can show or hide this, or the origin with the I feature. |
| 02:50 | Right clicking gives us a few more options so let's rename it as first plane. |
| 02:56 | Renaming these isn't necessary but it can come in handy for quickly identifying different datums. |
| 03:03 | Especially when you're first starting out. |
| 03:05 | We could also use this as a reference to create a new offset plane. |
| 03:09 | Let's set the offset distance to 50 mm, we can also see these features on our timeline down the bottom of the screen, first plane and plane two. |
| 03:18 | Right clicking the first plane gives us some of the same options as well as a few new ones. |
| 03:23 | For now, let's just edit the first plane. |
| 03:25 | If we change the reference plane from the right plane to the front plane, and change the offset distance from 35 to 72 mm, now we can see that plane two moved to a first plane. |
| 03:36 | This is because it references the feature. |
| 03:39 | This is something we must keep in mind when modifying features that are referenced by other features. |
| 03:44 | It's a real advantage in making fast modification but can cause errors or prevent the model from regenerating if we get it wrong. |
| 03:51 | Fusion360 does make this easy to spot though as the features in the timeline will usually be highlighted yellow or red when we have references that need to be updated or repaired. |
| 04:02 | Moving on from offset planes, let's head back to the construct tools up the top. |
| 04:07 | Now we've seen how they work, most of these tools are pretty self explanatory going on their name alone and may or may not be useful depending on what features we have available to use as references. |
| 04:18 | So let's open a model I prepared earlier and have a look at a couple of the most commonly used construction tools to get a better feel for how they work before we move on. |
| 04:27 | If you'd like to follow along, pause this lesson now and check below this video module to find a link to download the exact same file. |
| 04:34 | Once you have it, using the data panel, we can upload the file and then double click to open. |
| 04:40 | As you can see, it's a simple 3 bolt flange for an exhaust. |
| 04:44 | Let's use the tangent plane tool to create a plane that's tangent to the internal curve's surface. |
| 04:51 | Tangent in this context refers to a plane or straight line that just touches the edge of a curve but if extended, doesn't pass through it. |
| 04:59 | We can start by showing the origin by clicking the I symbol. |
| 05:03 | For the reference plane, we can see that it won't let us select the top plane as it's not suitable for a tangent to the face we've already selected. |
| 05:10 | Let's choose the front plane and rather than have the new plane parallel to this, let's set it at an angle of 15°. |
| 05:17 | You can use a negative value here as well to quickly switch to the other direction. |
| 05:21 | Now you can see that we've created another plane that's tangent to the inner curve surface of the model and at a 15° angle to the front plane. |
| 05:30 | Heading back to the construct menu, axis through cylinders is another commonly used construction tool and about as simple as it gets. |
| 05:38 | We can use it to select any curved face on the model and we can get an axis through the centre of that curvature. |
| 05:45 | Constructing an axis through our bolt holes would be useful if we wanted to model the bolts at a later stage for example. |
| 05:51 | Let's quickly look at another way to create an axis using the two planes tool before moving on. |
| 05:56 | Like we discussed earlier, the X, Y and Z axes are on the intersection line of the top, front and right planes and we can easily create a new axis through two planes or a plane and a surface of a part like we see here. |
| 06:08 | There are plenty of useful tools found in the construct menu that can be used to create datums but we'd be here all day if we went through each one so let's just leave it at that for now. |
| 06:18 | I strongly encourage you to spend some time getting to know each one and how it works. |
| 06:22 | So let's quickly recap the important points. |
| 06:25 | First understand that datums are reference features that can be used in the construction of a model. |
| 06:32 | There are three main forms of datums, planes, axes and points. |
| 06:35 | The tools used to create datums are very self explanatory, thanks to how they're named so make sure you put in the time to get to know them, seeing what reference features are required and how changing the inputs affects the resulting datum. |
| 06:49 | Luckily for us, the info boxes that pop up when hovering over a tool in Fusion360 are great for giving us a quick rundown on what's required so don't forget to have a look if you get stuck. |
