3D Modeling & CAD for Motorsport: Canvases
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Canvases
10.04
| 00:00 | - Before getting stuck into a new design, specifically one that needs to fit or interface with an existing part, a designer would traditionally make a basic hand drawn sketch of the existing geometry and add the important dimensions to it. |
| 00:14 | An alternative method is to use a canvas in CAD. |
| 00:18 | A canvas is really just an image that we add to the workspace that can be used as a reference to sketch and design from. |
| 00:26 | The image might be a photo of the surface that we want to design a bracket to mount to, it could be the outline of an existing bracket that we want to trace and copy the design, or it could be a technical drawing of the part with orthographic views. |
| 00:41 | Additionally, for smaller parts that can be removed from vehicles, we can also use a regular flat bed scanner like what most people have in their home offices to get the orthographic views on a flat surface. |
| 00:56 | These can provide excellent resolution and accuracy for locating holes or getting flat surface profiles. |
| 01:02 | Just be careful not to scratch the glass or place heavy objects on it unsupported. |
| 01:07 | We can also place a ruler on the scanning surface to get a really accurate reference for calibrating our part, which we'll be covering soon. |
| 01:16 | Either way, the benefit of using a canvas is to help us line things up and follow existing forms to get an idea of what will look at work the best as well as saving time taking measurements and going back to the existing part to check if our design will fit. |
| 01:32 | Before we even fire up our CAD software there are some things that we need to get right to set ourself up for success with our design. |
| 01:40 | In the case where we're taking the photo that we're going to use, as opposed to using an image we've found or been given, we want to make sure that we take a photo from a good angle that'll be easy to work with. |
| 01:52 | Essentially we want to take photos that represent the standard views of the technical drawing. |
| 01:58 | A view at an angle for example isn't going to be much use. |
| 02:02 | This isn't a photography course but there are a few things that need to be considered, most importantly we want to try to minimise distortion. |
| 02:10 | Distortion is deformation that occurs in an image because of the lens and perspective. |
| 02:15 | If we're using an image for dimensional reference and it's distorted, it can lead to inaccuracies. |
| 02:23 | Generally the higher the focal length of the lens the less distortion we get and we can also avoid distortion by not being too close to the object and keeping it centred in the photo frame. |
| 02:34 | Unfortunately a standard smart phone lens usually has a short focal length of around 25 mm. |
| 02:41 | This means that we're going to get some amount of distortion but that doesn't mean the photos aren't useful, we just need to take some extra care. |
| 02:49 | And with that said, if you're using a newer phone with multiple lenses, the longer telephoto option, the iPhone's 77mm zoom lens for example, is a great choice. |
| 03:01 | Regardless of how good our photo is, we still need to check the image dimensions to physical measurements, ideally in multiple directions. |
| 03:09 | We'll need to scale our image to match these physical dimensions we've taken. |
| 03:14 | If your photo wasn't taken from the best angle, or you have a lot of distortion, you may notice that while one measurement is correct, measurements in other directions are not. |
| 03:25 | It is possible to scale the image by different amounts in each direction but this isn't ideal and we're quickly losing accuracy. |
| 03:32 | Let's take a look at an example of using canvases in Fusion 360 to create a design. |
| 03:37 | For this we'll be looking at a front strut tower in an engine bay and we're going to get set up to start designing a strut tower brace. |
| 03:46 | I've already taken some photos of the car which you can find copies below this video module if you want to download and follow along, or you can always try taking some of your own car. |
| 03:56 | Make sure you store them in a known location on your computer or like I'm doing now, upload them straight to the project folder. |
| 04:03 | I find PNG image files work better than JPEGs for keeping the original proportions true when bringing it into CAD. |
| 04:12 | I also took some measurements on the car to check and calibrate our model in a common step. |
| 04:17 | The spacing between each strut tower stud is 95 mm centre to centre. |
| 04:24 | The first thing we need to do is bring in our images and position them in our workspace. |
| 04:29 | In our standard design workspace under the insert tab in the toolbar, we can select canvas. |
| 04:36 | Then from our project folder or a location on our computer, we can select the first image we want to use which in this case will be strut tower front view. |
| 04:46 | Next we need to select a plane or flat face to apply the image to. |
| 04:50 | In this case we'll choose the front plane. |
| 04:53 | Making sure the image is the right away up, we want to roughly centre it but we'll come back to position it soon to get it exactly right. |
| 05:01 | There are some scaling and opacity options that we can change from here but we'll leave them as they are for now and finish the insert canvas function. |
| 05:10 | When I took this image with an iPhone, the key things I focused on were making sure the phone was level, not on an angle and I also wanted the mounting face of the strut tower to be completely in line with the camera angle so I couldn't see the face but it also wasn't sloping away from the camera. |
| 05:28 | Now we want to scale the image to the correct size, this is best done by using the calibrate tool which we can find by right clicking the canvas in the browser. |
| 05:37 | It's good to make sure we're looking directly at the front plane to make sure we can see it clearly. |
| 05:42 | With the calibrate function active, we now want to set the distance between two points that we have a physical measurement from. |
| 05:50 | in this case, I know the top of each stud is 23 mm from the top surface of the strut tower so we can carefully click these points and set this to 23 mm which will scale our image up to set this dimension. |
| 06:05 | The calibrate tool can also be used to check other dimensions that we might have. |
| 06:10 | Again these would ideally be in different directions to make sure the image isn't distorted. |
| 06:17 | I know the studs are M10 so we can check the distance across the threads is about 10 mm. |
| 06:23 | Before we insert the other image we need to finalise the position of the first image and create a new plane for the next image. |
| 06:32 | Let's right click the canvas and select edit feature, then move the position so the origin is on the strut tower mounting surface directly in the centre of the lower stud. |
| 06:43 | This is an easy to locate point that we can use to position our next image. |
| 06:48 | We want to apply the next image to a plane that's in line with the mounting surface so let's look under the construction tab and choose the plane at angle tool. |
| 06:58 | Now we select the Z axis as the reference and look at the front plane. |
| 07:02 | We can see that an angle of about -12° puts the plane in line with the mounting surface. |
| 07:08 | Now we click insert canvas and select the strut tower top view image to be applied to our new plane on an angle. |
| 07:17 | This photo was taken looking directly at the mounting surface with the two studs closest to the front of the car level with each other. |
| 07:25 | If we drew a straight line through these studs, they'd actually be parallel with the axle of the car. |
| 07:31 | We won't adjust the position just yet, let's first calibrate the canvas, looking directly at the plane so the studs are all spaced at 95 mm to match the measurement taken from the vehicle. |
| 07:43 | Then we can adjust the position of the new canvas by right clicking and selecting edit feature. |
| 07:50 | So the origin is in the centre of the bottom stud. |
| 07:53 | Now if we look at the canvas from an angle, we can see our images are aligned in the different planes with the two front studs aligned on both images. |
| 08:03 | Everything is also now to scale and giving a good dimensional representation of the strut tower mounting surface. |
| 08:10 | From here we're ready to start modelling by sketching on the angle plane following the edges and forms, without needing to go back to the car and take measurements. |
| 08:20 | We can also position the mounting holes to line up with the studs, a clearance hole to access the top of the damper or more of a cutout if we have camber adjustable top hats and an outline that suits the form of the strut tower. |
| 08:34 | Then all we need to do is extrude the design and we'll have a good understanding of how it would fit in the engine bay. |
| 08:41 | For this example, one view could have probably been enough but two views really helps show the geometry and the height that we can work with. |
| 08:49 | Like I mentioned at the beginning of this module, we want to use photos that essentially represent the standard views of a technical drawing. |
| 08:58 | We could have used three canvases, one for each origin plane or even more but it'll probably start getting confusing and unclear. |
| 09:06 | Before we finish, let's recap the main points from this module. |
| 09:10 | Canvases are essentially just images that we can add to planes or flat faces in the workspace and use them as references to design our model around. |
| 09:20 | We want to be mindful when taking the photos to make sure we take something that's useful and will help us make an accurate design that will fit with existing parts. |
| 09:30 | The key things to think about here are taking photos directly at objects and minimising distortion. |
| 09:36 | With some care, we can get great results even with older smartphones. |
| 09:41 | Then we can insert the canvases into our workspace and calibrate the sizes to match the measurements we've taken. |
| 09:48 | Once we're comfortable the canvases are to the correct scale and in the right position, we can start modelling our design using the images as guidance, saving us time taking more measurements and going back to check if the design will fit. |
