Let's talk about the following three
Fusion 360 features: extrude, press pull and offset face. They seem to have a lot in
common and many users find it confusing to decide which feature to use. I'm going
to give you my recommendation upfront. You should be using only the extrude and
offset face features and avoid using the press pull feature. I want to stress that
there is no right or wrong answer here but this is just my personal opinion. If
you are interested in finding out how I arrived at that conclusion, I would like
to invite you to follow along in the next few minutes. At this point I, would
also like to credit Adam for asking the question that prompted this video. We
shall start with a very quick overview of the extrude feature which resides under
create. You start by selecting a close contour as the profile. This can be in
the form of a sketch or a face of an existing body. You can only select planar
sketches or faces. Despite this limitation, the extrude feature is more
than capable of creating non planar features by adjusting the start and
extent conditions. One important aspect of the extrude feature is that features
are created in a direction that is normal or perpendicular to the sketch
plane. Bear this in mind when we talk about the offset face feature. The offset face
feature resides under modify. It shifts the selected face or faces of existing
bodies. It intelligently recognizes tangent faces and offsets them in a
chosen direction. This is especially useful for moving multiple faces that
are not planar. Here, we have a split face on a cylinder. In the earlier example with
the extrude feature, the feature was created in a direction normal to the
sketch plane. If you use the offset feature to do this, what you get is a
feature that extrudes normal at all points to the existing surface. This is
the important difference between the two features. Let's move on to the press pull feature,
which is also under modify. The tool tip gives a pretty good summary of what it does.
Put it simply, it is the same feature as offset, extrude or fillet but with a
different name or skin if you will. If you start the press pull feature and
select a sketch profile, the feature changes into an extrude. This is the same
exact feature as what you would have had you started the extrude feature
directly. If you start a press pull feature and select the face of an
existing body the command changes to an offset command. In this case, we have
selected the top face of the cylinder. If the offset type is set to a new offset,
this will stack an additional height to the existing cylinder. This will also
appear as an extra step in the timeline. If the offset type is set to modify
existing feature or automatic, it will recognize that you are trying to change
the previous extrude height. Once you make the change and enter, there is no extra
step in a timeline. If you go back inside the existing extrude feature, you will
see that the extrude depth has adjusted accordingly. Starting the press
pull feature and selecting an edge of a body changes the feature to a fillet. If
you click on an existing fillet, it changes to an offset feature that allows
you to change the fillet but does not give you full access to the fillet
feature. After all that, I hope that you are still with me at this point. So why am i
critical of the press pull feature? First, the press pull feature is a duplication
of functions that are already well served by the extrude, offset face and
fillet features. As a feature by itself it does not add any value to the abovementioned 3 features. Second, it de-emphasizes design intent. The press
pull feature allows users to conveniently adjust faces with little
regard to design intent. For example, the design intent in this case
is for the cylinder to be 50 mm above the top face of the cuboid. Suppose that we want to adjust the height of the cylinder and decided to use a
press pull feature. If we use new offset as the offset type and add the value
accordingly, we would have lost the original design intent of taking
reference from the top face of the cuboid. This would also add an
unnecessary step to the timeline. Well, you might argue that we can use the
modify existing feature option so that we can edit the existing extrude without adding a step in a timeline and still preserve design intent at the same
time. But here comes the question: Why use the press pull feature in that way when
we can easily go back into the existing feature by right-clicking, going to edit
feature and change the values from there? What about imported models with no
design history to speak of? Let's perform a press pull on one of the faces. The
feature changes to an offset. Let's try an edge. The feature changes to a fillet.
Again the press pull feature fails to add any value to the exiting features
that it replaces besides just having a different name. Is there any point at all
to the press pull feature? I would like to think that it was created with good
intentions on the part of Autodesk to lower the barrier to entry for newcomers
to CAD. The press pull feature houses three major commands under one easy to
understand, intuitive name. It is in the spirit of the direct modeling technique
where the model is treated like silly putty where users can freely add and
remove material or press and pull much like a sculptor. It reduces the need understand
each feature more intimately. In product demos, it looks highly impressive. However
from the perspective of designers and CAD users that value design intent and a
streamlined user interface, the implementation of the press pull feature
is awkward at best. So my recommended workflow is as follows.
Always think about using the extrude feature first. It is the most flexible
tool of the 3. Take note that it is fully
capable of creating non-planar features even though the sketch profile has to
be planar. It is just a matter of knowing how to adjust the start and extent
conditions. Take note also that it creates features normal to or perpendicular to
the sketch plane. If you need to create features that is normal at all points
to a non planar face, use the offset face feature. The offset face feature will
also allow you to select multiple faces for offsetting. If you need to adjust
faces, instead of mindlessly selecting a face and thinking of ways to shift that
face, always think first about how that feature was created in the first place
and then go back inside the original feature and make changes accordingly.
This will preserve design intent and prevent an unnecessarily bloated
timeline. There are cases where it might be difficult to adjust the original
sketch due to the complexity. In this case, it is perfectly fine to use the
offset tool. Even if you decided forgo design intent, just remember that the
offset face feature can do everything that a press pull feature can. Lastly I want
to emphasize that there are no features that the press pull feature is capable
of that cannot be achieved by either the extrude feature, the offset face feature or
the fillet feature. I hope that this does not come off as a long rambling rant. This is
not meant to be a criticism of users who have found the press pull feature useful
and have incorporated it into their workflow without any issues. This video
was meant to hopefully provide users with a more complete picture on the 3
features in question so that they can make a better judgment on which feature
to use in different situations. If you agree or disagree with me, do leave a
comment below.
