Create motion with assembly joints

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Create motion with assembly joints.

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After completing this video, you'll be able to

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use a line and capture position to position components.

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Apply an as built joint, apply a joint and create a rigid group of components

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to get started.

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We want to open the supply data set sample engine assembly joints dot F 3D.

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We're going to be looking at using

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tools like aligning capture for positioning components.

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We're going to talk about applying as built joints

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and joints and creating rigid groups of components.

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The first thing that we want to do is note inside of our browser,

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the cylinder is currently pinned or grounded

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and the crank holder which is another component

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that's hidden is currently grounded as well.

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What we're going to do is start by hiding the cylinder

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and we're going to focus our attention on the rotating assembly.

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Currently, the rotating assembly has its own coordinate system

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and all of the sub components also have their own coordinate systems.

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What fusion needs to understand is how

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each of these coordinate systems will interact

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with the rotating assembly as well as the top level of our design.

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The first thing that we're going to do to get

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started is we're gonna move the piston out of the way

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and we're going to capture its position,

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capturing the position of something in fusion adds a feature to the timeline.

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This position feature can be suppressed,

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deleted or rolled back at any point in time.

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But we're using this as a way to better

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understand the use of joints and as built joints,

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we're also going to temporarily hide the crank and focus our attention on

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the connecting rod as well as the big end and small end bearings.

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These three components are gonna move

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with each other in a rigid fashion.

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We don't need to apply a joint between them

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and we want to make sure that they always stay rigid.

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There are a couple of ways that we can do this

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because they're currently in the correct location. We could use an as built joint.

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An as built joint allows us to create a joint for motion

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based on a components, current location

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using an as built joint for a rigid type of motion

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can be used in this instance.

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But because it can only work on two selected components,

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we would have to do this twice.

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There's a better way when we have multiple components

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that need to stay rigid with each other.

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Under the assemble menu, we have what's called a rigid group.

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Using a rigid group allows us to lock the

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position of multiple components relative to each other.

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Once we say OK.

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Moving the connecting rod now moves both the big

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end and the small end bearing with it.

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We're going to use revert position.

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Next. Let's go ahead and bring the crank back.

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The crank currently has a revolute joint that

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allows it to rotate about the crank holder,

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which is a hidden component.

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What we want to do here is revert its position

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and make sure that we understand the current

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location of the connecting rod relative to the crank

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to do this. We can go to inspect and take a look at a section analysis.

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We're going to use the default xy plane

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and note that currently, these are not in the correct location.

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The connecting rod can't use an as built

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joint because it's not in the right location.

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So what we're gonna do is cancel our section view.

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We're gonna move the connecting rod out of the way

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and we're gonna capture its position as well.

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Remember that as built joints only work based on the current components location.

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So if we need to have this in the correct spot,

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then we need to make sure that we add a

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traditional joint because they're not in the correct location.

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Now, if you remember back,

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the piston was in the right location originally and we captured its position.

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One thing we can do is select

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right click and delete that

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and we can roll back before we move the connecting rod in

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this case.

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Now,

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the piston and the connecting rod as well as the

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small and big end bearings are in the correct location.

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And we can make use of an as built joint

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for this. We're gonna make use of a revolute joint.

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So navigate to the type revolute,

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select the components. In this case, the connecting rod and the piston.

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And then we need to select the axis of revolution.

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This can be any cylindrical reference on the piston,

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the connecting rod or the small end bearing,

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we can say, OK.

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And now we can go back, roll forward

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and you can see the piston itself as well

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as the connecting rod and the bearings all moved.

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Now, we need to apply a joint between the connecting rod as well as the pin on the crank

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to do this. We can use the assembled joint command.

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We're going to select the motion type as revolute

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and the position can be done a few different ways.

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If we hover over the center position of our big and bearing,

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we can hold down the control key

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and navigate to the center location.

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We can do the same thing for the pin hover over the pin,

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hold down the control key and navigate to that center location.

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We're gonna say, OK.

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And now everything should move as intended.

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We'll note that the piston itself doesn't move properly

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because it's not properly constrained inside of the cylinder.

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So the last thing that we need to do

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here is constrain the piston inside of the cylinder

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because the original location of the connecting rod was not correct.

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We can see that the piston is not in the right position.

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So we can't use an as built joint.

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We need to go to assemble and we need to use the joint command.

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Once again,

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we could roll back in our timeline and we could add the joint to the piston earlier on.

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Or in this case, we can come through and add a different type of motion

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because the piston needs to move up and down. This would typically be a slider joint,

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pistons typically also are allowed to move slightly inside of the cylinder bore.

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And you may find that you need to use something like a cylindrical type of joint.

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Let's go ahead and apply the cylindrical type of joint in this instance,

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position one is going to be the top center of our piston.

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So once again, hover over the face, hold down control and select that location.

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Location. Two is going to be the top center of the cylinder.

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So find the edge, hold down, control and select that location,

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we're gonna say, ok.

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And now we've added the joint that allows the piston to

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move up and down inside the bore of the cylinder.

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And we've added the revolute joint between the connecting rod bearings and

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the piston as well as the connecting rod and the crank.

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This gives us the correct motion that we need for this type of rotating assembly.

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It does take a little bit of work to better understand

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how these joints interact with the rest of the assembly.

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But keep in mind that if you design all your components in the correct location,

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you can make use of as built joints, which is quite a bit easier.

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If the components are inserted into your assembly,

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then you'll need to use the joint command

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at this stage. Let's go ahead and save this assembly

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and then we can go ahead and move on to the next step.