Filleting edges, trimming, boolean split help


#1

Hi, I’m new to Rhino and have been exposed to it for a few weeks. I’m working on model for my product design class and I’m having trouble making it come alive. This is what the physical model looks like:

Some more views just to clarify:
Top view

Side view

Front view

Back view

I started working on this model two weeks ago and since then I’ve been stuck. I’ll explain what I’ve done so far in Rhino.

  1. I drew the front view cross section profile
  2. I drew the side view profile
  3. I disregarded the top view because after several hundred attempts it became too complicated for me to incorporate
  4. I extruded the front view curve and side view curve so that they intrsect.
  5. I then used the trim command to get rid of the excess extruded material
  6. I ended up with this:

I have tried using the boolean split command and I do not get a result.

I tried to fillet the edges but an error message pops up telling me there is a failure in bulding corners.

At this point, I’m not sure what to do and how to go about completing this thing. Any help or suggestions would be greatly appreciated.

I’ve attached the file for reference.

11:10.3dm (2.5 MB)


#2

Depending on how picky you are about the sharpness of the profile, you could try point editing.

Fig 1. Perhaps something like this? Starting form an ellipsoid, using degree 5 and U=8 V=8 (set with the Rebuild command) :

// Rolf


#3

another method would be to use the ‘PictureFrame’ command, create your curves from 3 views, then possibly use NetworkSurface command


#4

FilletEdge seems to work for the tiny (.02) fillet that is in your file. You may have missed some of the edges
when selecting.

If you want larger fillets you will need to start with curves that have better continuity and don’t put small fillets in the convex corners of the construction curves because that will limit the size of the fillets that can wrap around those corners.

In the enclosed file I reconstructed the curves and redid the extrusions and the resulting polysurface will support fillets up to about a radius of .3 with FilletEdge. And will support fillets up to about a radius of 0.8 if you make the fillets with FilletSrf command.

11_10x.3dm (557.5 KB)

Looking at your pictures it doesn’t look like the sides of the object are straight so extrusion is a bad choice for making the sides, Here is a file where I I used the same technique but made the sides curved using loose lofts instead of extrude.

11_10x2.3dm (489.9 KB)


#5

Hi Jim, thank you so much for taking the time to help me with this. Could you explain what you did when reconstructing the curves and redoing the extrusion of the first file? I realize now that the small fillets near the front of the object are problematic for the filet command because they are so small and tight. Thank you for pointing that out.

Could you explain your process when making the second file? Sorry if I’m asking too many questions, I’d just like to fully understand this so I can do it on my own.

Thank you again


#6

Hi, thank you for the suggestion. I will give it a shot and see what I can come up with.


#7

You really shouldn’t be posting files for students. Screen caps are fine to point them in the right direction.


#8

Here is a file showing the steps for making this with extrusion. I used the curve command and then point editing to create the curves that are simple and are close to the shapes that you had. You can use curvaturegraph to compare the curves. Taking a little time to create clean curves will save you tons of time down the road.
11_10extrude.3dm (600.6 KB)

The second version was made by using the same process except that the top, bottom, front and side surface were made using loose lofts instead of extrude.
Each of the lofted surfaces are made with 4 curves. The 4 curves are made by creating 3 copies of the same curve and then using scale2D and point editing so that when lofted the surface is curved instead of straight like extrude makes. Loose loft with parallel sections that are all derived from one curve can be used to make very smooth well behaved surfaces

If students want to learn they should be encouraged. If they don;t want to learn they are only cheating themselves.


#9

Jim, I appreciate this so much. I’m a visual learner and the break down helped me understand your process immensely. I will try to replicate what you have done and play around with different curve combinations to get a better feel for those commands. Stratosfear doesn’t realize that some people like to have the physical file to explore and tinker with when learning something new. Thank you for your help.


#10

It’s been a problem in the past. That’s why it’s discouraged. It’s a big reason why I only post screen caps. If it’s not in the community guidelines it should be.


#11

I agree, when I was learning web design back in the 90’s someone showed me how to “View Source”. That helped me immensely playing with other peoples code. I am also a visual learner and sometimes a screenshot will suffice, better than lots of words. Othertimes I need and share files to see what is going on. A screenshot sometimes is more confusing, I need to twirl the object(s) around to see what is going on.

Cheaters will always be cheaters

Happy Learning, Welcome to Rhino3D :slight_smile:


#12

nonono not so fast guys,

what can one learn from getting the finished file smashed into the face :wink:, yes its nice and comfortable also the last possible resource when you are completely stuck, but that does not help you to develop yourself in matters of dealing with future tasks especially during your learning process. it will make you depend on help all the time. whats more you might also discover many new things while doing so, learning new things which others had not seen yet and whom you can help with later on.

this is a very simple task and i also would believe showing the directions would suffice plentiful.
learning by doing still has quality.


#13

Discouraging example files would seem contrary to how this community has functioned for years. I understand the sentiment of not doing other peoples homework, but in the end, the reason someone is a student is because they want to learn. The amount of information that can be gleaned from looking at the actual geometry in a file, and potential for learning good modeling practices, is in my opinion unparalleled.

Also, when it comes to filleting (and many other things as well), there are not many better people to learn from than lowercase jim.


#14

The reality is academic fraud has become a serious problem in the age of the internet. Ask a teacher, you would be shocked at how bad it is. Posting an example file is ok. Doing a student’s work for them is most definitely not.


#15

Thanks, showing how something is done and doing their work are 2 different items. I totally agree wth you on this point.

In my view, with a daughter in grade 9, academia needs a shake up anyway. Schooling to the lowest common denominator has become a problem.

This is the age of information and not always correct, but we have to support the people that want to learn, as opposed to the people that just was to get ahead. Not easy!


#16

i am sure you are very right there.

thankfully Finland has started efforts in changing its school system fundamentally.
the only question is will that idea make it up to the collage or university levels.


#17

Both my father and father-in-law are tenured professors, so it is a situation that I am familiar with. I have heard a great number of highly entertaining tales involving the discovery and confrontation of plagiarists; it is in fact an annual Christmas visitation ritual of “who has the most entertaining story of a failed cheater”. However in all these stories, the villain is never easy access to knowledge, the villain is the lazy student who is cheating themselves.

While limiting access to the solutions to problems, clever and clean works which are great examples of how things can be done and which should be digested, understood, and emulated may provide some hindrance to those who are not interested in learning for themselves, it also will be a hindrance for those who do want to learn.

I would agree that passing others’ work off as your own is a problem, but I don’t think retarding an honest student’s progress is the solution. Both my father, now retired, and my father-in-law, still teaching, lament the fact that they have to watch for cheaters, but neither feel access to information is the problem (if anything, for them, it has made finding plagiarists easier). Rather, they feel making efforts to ensure students understand what is acceptable work, and when using others work what citation is needed, is a better course of action for all their students. I tend to agree.