3D Modeling & CAD for Motorsport: Step 2-B : Modelling - Core Structure
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Step 2-B : Modelling - Core Structure
09.17
| 00:00 | - With our flange sketch out of the way, we can move forward and begin creating our 3D model for the valve cover. |
| 00:06 | This process will start with creating the flange itself using the extrude tool. |
| 00:11 | We'll select the main profile, being sure to include the areas that we plan to add material with our previous sketch but leaving out the circular profiles for the spark plug holes and camshaft reliefs. |
| 00:24 | We do however want the mounting holes to be filled in. |
| 00:28 | This is a simple extrude feature starting on the profile plane and extending up to form the flange. |
| 00:34 | Naturally creating a new body since this is our first 3D solid body in the design. |
| 00:39 | We'll actually get 4 new bodies in this case since the areas around the spark plug holes aren't connected to the outer flange but we'll merge these back together later on. |
| 00:49 | We want to mount the valve cover to the head with M6 cap screws that will sit flush with the surface. |
| 00:55 | And this is most efficiently done using the hole tool. |
| 00:58 | To give our hole tool references to position the holes, we'll quickly create a new sketch on the top of the flange and project the hole centre from the first sketch onto this new one. |
| 01:08 | Then we can open the hole tool and select each of these for the sketch points, creating a countable hole to suit the dimensions of the hardware. |
| 01:18 | Before moving on, let's bring in another component from our data panel that will help us model the rest of the valve cover. |
| 01:24 | This is a simple model I've made of the ignition coils we plan to use. |
| 01:29 | These are commonly from the VR38 DETT engine in the Nissan R35 GTR and there are a few different variations in the coil around the length of the stalk. |
| 01:40 | I've taken some measurements using some coils we have on hand and our spare cylinder head that will help us position this component exactly where it needs to be. |
| 01:49 | Using the joint tool and for component one which will be the coil, we'll use the origin snap point in line with the bottom face of the top section of the coil and in the centre of the stalk. |
| 02:01 | For component two, which will be the valve cover, we'll use the origin point in the centre of the spark plug hole on the bottom surface where the flange mounts to the cylinder head. |
| 02:11 | Then use the offset function to set our coil position to match our measurement and rotate the coil so the mounting boss is towards the front of the valve cover but offset to one side. |
| 02:22 | This will help with the coil harness routing past each coil. |
| 02:26 | We obviously need 3 more coils so rather than repeating this process, it'll be more efficient to use the rectangular pattern tool with the object type set to component and select the coil. |
| 02:38 | Choosing the direction and spacing to match the spark plug holes. |
| 02:42 | Moving on, we'll start modelling the main body of the valve cover and this is going to to require some more sketching, again on the top plane. |
| 02:51 | The profile we're about to create essentially forms the outer walls with an extrude. |
| 02:56 | Using the project tool allows us to reference a lot of the flange we've already created to help speed things up. |
| 03:03 | Starting with some simple lines around the outside with the line tool to form the main structure, then the circle tool concentric with the mounting holes to leave some clearance for tool access. |
| 03:14 | We'll use the trim tool to remove unwanted parts of the profile and connect the open parts of the profile with the arc tool. |
| 03:22 | The final thing we'll add to our sketch is provisions for our breather ports, with the line tool and mid points to position them vertically. |
| 03:29 | If we use the line tool and click on the end of the line we can hold to make a tangent arc. |
| 03:35 | I want there to be more slope on the front angled face since this will be viewed from the front and tie into the rest of the design. |
| 03:44 | We'll use the trim tool as the final step around the breathers to remove unecessary lines and tidy things up so it's easier to select our main profile when it comes to using the extrude tool in the next step. |
| 03:57 | The last thing to do for this sketch is to round the remaining sharp corners with the fillet tool or in some cases it can be helpful to use the 3 point arc tool. |
| 04:06 | That finishes the sketch so we can fire up the extrude tool, selecting the entire inside profile we just created. |
| 04:14 | The start plane for this extrude will actually be the top of the flange which we created earlier which is done using the object setting and selecting the surface. |
| 04:23 | Then we simply create an extrude of this profile to whatever height we want with the operation set to join to the existing bodies. |
| 04:31 | Some tidying up is required around the bottom of the breather blocks simply using another extrude down to the base of the flange and then using the fillet tool to remove the sharp corners so the part can be machined. |
| 04:44 | Moving on, we'll start to add some curvature to the main structure of the top of the valve cover. |
| 04:50 | A lot of this depends on what the desired aesthetic of the part is and that's going to be different in each case but the direction for this valve cover was a nice clean part with a large radius round on the major edges. |
| 05:03 | To start this process, we'll round the top edges along the side of the part. |
| 05:07 | From the front cam gear section right to the back. |
| 05:11 | Rather than using the fillet tool, we can just use another extrude to cut a curve into the part the whole way along each side that doesn't follow every detail. |
| 05:21 | Another sketch first though, this time on the front of the flange, projecting the sides of the valve cover and using the 3 point arc tool with tangent constraints to make our profiles. |
| 05:31 | A little bit of a creative approach is required to get the curves looking even on both sides even though the main structure of the valve cover isn't symmetrical. |
| 05:41 | From here, we can finish this sketch and open the extrude tool then select the arc profiles from the sketch we just finished and cut through the entire part. |
| 05:50 | Next we'll use a similar method on the front edge, starting with a sketch on the flat vertical surfaces on the side of the flange. |
| 05:59 | Projecting the edges again, and also using the 3 point arc tool, tangent to the top with the same radius as the cut down the side of the part. |
| 06:07 | We can include something for the rear of the part here as well since the extruded cut feature will be in the same direction anyway. |
| 06:15 | On the back of the part, we'll cut a straight sloped edge into the valve cover rather than a curve to help clear the scuttle panel and for this we need an angled line between the projected edges to form a closed profile. |
| 06:30 | Then it's just a matter of using the extrude tool to cut these profiles through the entire part. |
| 06:35 | With that, the 4 main edges of the top of the part are formed but we'll come back later to finish them off with smaller more detailed fillets. |
| 06:43 | Before finishing up this module, we'll make the remaining major changes to the core structure of the valve cover. |
| 06:50 | The valley for the ignition coil is the main one of these and we'll use the sketch on the top surface of the part to make this. |
| 06:58 | Projecting some edges and the spark plug holes for reference, most of this can be done with a simple rectangle. |
| 07:04 | But it's helpful to use mid points and constraints to centre the rectangle over the spark plug holes without protruding too far into the camshaft area. |
| 07:13 | From here it's another extruded cut using our skeetch profile but this time with the extent set to the bottom surface of the top section of the ignition coils, as we want them to sit flush with the valve cover here. |
| 07:26 | We'll also use a taper angle so the walls slope in. |
| 07:29 | This just makes a bit of a softer look to the cut but thinking ahead, it might help cleaning the area and even with airflow over the coils. |
| 07:38 | Next is maybe the main step that you might have been envisioning and that's clearing out the inside of the valve cover. |
| 07:45 | While it might be possible to do this with the shell tool since this is roughly how it functions, it's actually going to be more effective for this geometry to use an extruded cut again. |
| 07:55 | With an extruded cut, we can select the bottom inside surface of our part as the profile and choose the top outer face of the part as the extent. |
| 08:04 | The important part is changing the extend preference to adjacent face so the extrude will only go up to the surfaces that are adjacent with the top face. |
| 08:15 | We also want to use an offset here to leave material in place around the top of the part. |
| 08:21 | I've set a general rule for this part to make the minimum thickness of the main walls 5mm. |
| 08:26 | This is massively overkill and we may pay a price in weight but with the previous history of the old valve cover and the risk of this breaking and not only wasting such an expensive part but possibly damaging the engine and having to retire from the race, I'd rather be cautious. |
| 08:43 | The last thing we'll address for now is access to the munting holes in the centre of the part. |
| 08:48 | This is as simple as using a circular extruded cut down to the level of the outer flange top surface to open access to the hole. |
| 08:58 | And with that, we've just taken what was just the flange profile to something that resembles a valve cover. |
| 09:04 | Most of the structure is created at this point so moving onto the next module, we'll add all the features to make this part function, as well as some finishing touches. |
