I haven't worked in Inventor, but you can change the transparency of the wall/surface that gets in the way.
Then you are effectively "inside" the part/model. However if you rotate the model you will be "outside" the part for all other faces so it can be confusing.
Hold Shift when you RMB over the invisible wall to change it back.
You can change the transparency of the entire body (in multi-body parts) by right-clicking on one body in the feature tree and selecting 'Change Transparency'.
You can also use a section view, with 'show section cap' unchecked, and this will show the inside of your part from the location of the sectioning plane (which can be moved to any desired location).
You can also change the Display Style of the part or assembly to 'Hidden Lines Visible' or 'Wireframe'.
Hope this helps!
I've not found a way but it sure would be handy if we could. I didn't know Inventor could. For me it would be one of those Huge enhancements because my model is of a factory. Being able to fly through and view various areas from within would be incredibly helpful in presentations. The pre-programed walk-through just isn't very helpful if someone says, "wait go back and zoom up on that". Being able to actually work on stuff would be the bee's knees.
Yes, I really wish this was a feature. It's extremely useful when modeling large assemblies to simply fly around the model, around corners, and inside closed bodies.
I don't understand why this can't be an option, instead of these workarounds that is recommended...
You can "kind of" do it with View > Lights and Cameras > Add Walk-through.
Although the controls take some serious getting used to.
Most don't think it's something that needs fixing because there are ways to work inside. Like others have said, make a wall transparent or I sometimes section my model to work on inside.
You can't "fly through: like you can in I-DEAS, Inventor and some other softwares...
However, here are some other options
(some of them have been mentioned already):
I can't think of any others at this time.....if I do.....I will update.
There is a walk-through capability which is documented here:
Click on the 2 sub-topics to see details. You don't have to make a recording to do a walk-though but can use this functionality live when giving presentations/etc. as Scott has said would be useful.
The one thing I don't *think* you can do is use it while using modeling commands because walk-through itself is a command and you have to be in the command to use the walk-through control panel and mouse controls (so can't then call up other modeling commands). But, someone else more familiar with this functionality may know differently.