00:00 |
- The tools we've covered up to this point in the course have been either construction tools used to generate datums or creation tools which use those datums to produce solid bodies.
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00:10 |
Once we've created 3D bodies they can be altered with the modify tool set found in our solid modelling toolbar where tools like combined, scale and split can be found.
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00:20 |
Let's take a look at these three tools first.
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00:23 |
With the combine tool, we're able to merge multiple bodies together to form a single body.
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00:28 |
It's as simple as selecting the bodies we want to combine, though do keep in mind that the bodies need to be in contact with each other for it to work.
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00:37 |
This is similar to what can be achieved with the operation preference when creating the feature.
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00:42 |
But it allows for a little more flexibility and post processes.
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00:47 |
The split tool works in the opposite way to the combine tool.
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00:50 |
Splitting a single body into multiple.
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00:53 |
The difference worth noting here is that the split tools require datums or references from sketches for example to achieve the outcome we're after.
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01:02 |
The simplest way to do this is to create a datum plane through the body and then split it through that plane.
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01:08 |
With the scale tool, we can scale the object to make it bigger or smaller while retaining the relative geometry by using the uniform scale type.
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01:17 |
We can also choose to scale using the non uniform preference and scale the bodies by different factors in the X, Y and Z directions.
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01:25 |
Let's move onto a couple of modify tools that we're going to be using quite often when putting finishing touches on our models.
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01:32 |
Fillets and chamfers.
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01:34 |
The fillet tool here follows the same idea as the one we used in our sketches but in this case, is for 3D bodies.
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01:41 |
In a machining context, fillets refer to the rounding of sharp edges or corners, while chamfers are a straight, sloping surface to break a sharp edge or corner.
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01:51 |
Like a short 45° transitional face on a 90° edge for example.
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01:57 |
Finishing the corners and edges of parts with fillets and chamfers is a relatively simple process but it can go a long way for a more professional look and as we've learned in the design fundamentals section, removing sharp corners also helps reduce stress concentration.
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02:13 |
Of course fillets and chamfers are not just finishing processes, they can also be used to make functional features while creating our model.
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02:21 |
While these modify tools are relatively simple, we do have quite a lot of flexibility over the features through changing the radius type preference to allow for a variable radius.
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02:32 |
By doing this, we can modify the radius of the rounded edge along its length.
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02:37 |
This is handy when working with bodies that are irregular shapes or if there is a feature like a hole close to the edge.
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02:44 |
We may want to change the radius of the fillet near that hole to avoid it.
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02:49 |
Next up we have the push/pull modify tool.
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02:52 |
This can be used for simple additions or cuts to existing bodies just by moving the faces of the model rather than using the extrude tool which requires a sketch or existing profile.
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03:03 |
Likewise, the shell tool can quickly hollow out bodies and automatically identify existing features, saving the time of creating a sketch offset to the edges and then using the extrude tool to remove material.
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03:17 |
This process is ideal for shaving weight, as long as we understand the effect on the strength of the part.
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03:23 |
Now let's have a look at the draft tool.
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03:25 |
If you're familiar with the injection moulding or casting process, you'll be aware of the importance of drafts.
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03:31 |
For those who aren't, drafts are essentially the amount of slope or taper on a surface to help parts with ejecting from the tool after forming.
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03:40 |
Using the draft tool is a quick and easy way to apply this taper to existing faces.
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03:45 |
However it's just as easy to apply this taper with some of the creation tools while generating the body.
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03:51 |
For those of us who aren't using CAD in professional environments, it's unlikely that we'll be designing parts that'll be manufactured using these methods, due to the relatively expensive cost of the tooling.
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04:03 |
That's not to say the draft tool won't be useful for modelling other features, so just remember it's there if needed.
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04:10 |
As always, it's a really good idea to use the extrude tool to make some simple bodies and then experiment with the different modify tools available to get a feel for what we can change with what tool.
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04:21 |
To quickly summarise what we've covered in this module, the combine and split tools result in changes to the number of bodies but the split tool requires a sketch, plane or surface to divide the bodies.
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04:33 |
The scale, press/pull and shell tools are for modifying the overall structure of the body and rounds, chamfers and drafts are great for post processes, finishing the part once the general structure is defined.
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04:46 |
That's not to say these are the limitations, there are no right or wrong answers to modelling so use whatever tools however you need to in order to most efficiently model your design.
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