Precise modeling in rhino 5, Quoting and measuring


#1

Hello everyone
I am a new user of rhino and I have some questions about some features.
I would like to modelise an object already designed. I have the precise measurments of it but I don’t know how to create the object by applying these mesurments.
A picture speaks always better than words:

I want to extrude the red parts along the green path. The red parts are mainly circles exept at the end where it is ovals. all the guide circles (in red) have to be centered on the green path.
My question is how to place precisly the shapes to construct the shape and then how to link the different shapes to make the solide object.
Thank you for your futur advices

Paul


#2

Open the attached example file.

Revolve the blue profile curves around the red axis curves and trim(in the top view) using the green trim curves.HORN.3dm (275.5 KB)


#3

You can make the flared end accurately with a loose loft

LooseLoftX.3dm (118.0 KB)


#4

Good call Jim. Looks like I blew the end profile…


#5

Thank you it is exactly what i needed! But could you explain me the process to get to that, i am a beginner. So i drew my circles and my path then i choose the option revolve, but what should i select after?


#6

Paul,
Select the profile circle(cross section of the tube). Then start the revolve command. You will be prompted for an axis beginning and end. I usually draw a line or a couple points that I can click on to indicate the axis. Then you are prompted for the revolve angle. This is the beginning and end of the tube. If you click on “FullCircle” in the command prompt when you see it, Rhino will revolve your profile curve 360 degrees around the axis.

The revolve command doesn’t use a path curve. I just drew a circle for construction purposes.

There is a nice video of the revolve command in Rhino-Help

Jim


#7

ok, but how do you link the rovolve part with the oval ending part?


#8

Better to see what Jim did above. My revolve used a different profile and axis but did not create your exact end shape.
What Jim did was to “loft” the end piece.


#9

okay i tryed the loft loose, but i don’t understand i get this:


#10

In the model I posted earlier the flared bell is the only part made with the loose loft.
There are 2 surfaces one is a revolve and one a loft. They can be joined to form a polysurface

The enclosed file has instructions in the Notes for the revolve and how to make the 3 profiles that are lofted to create the bell.

-jim

LooseLoftX2.3dm (107.8 KB)


#11

I understand now how the second method work, but the first method (james) has the advantage of folowing the inner circle. But the profil of the end is a circle whereas the second method (jim) is an oval has i want. Do you know how to combine the two? for exemple doing a revolve but not circular?

Also I have some difficulties doing osnap opperations: for exemple how did you do precise segment perpendicular to an other segment? or segments parallel to each other?
Thank you


#12

I’m not sure what you want… I think James made the bell with ExtrudeAlongCrv. A revolved surface is by definition circular and has a constant shaped profile. You can make the whole thing as a single surface using Sweep2 or networkSrf or normal loft, but I don’t know that a single surface is better.

In the enclosed file there is an example of using sweep2. Sweep2.3dm (133.7 KB)

You can make a parallel line by either using Offset command or by copying the line. There is an option in the line command option to make a line perpendicular to another curve. You can also rotate (copy) a line 90 degrees to create another line perpendicular to an existing line.

In the model i sent before, the red line that is perpendicular to the magenta line is also tangent to the centerline circle. You can make that red line by creating a line (extension bothsides) that is tangent to the circle…

You can also use the perp osnap to make a line perpendicular to another curve. That one only works for the second pick point in the line command.


#13

Thanks to you I made the shape I wanted, but now I have two obstacles. The first thing is this part


I want to make the ending part with the edge smooth. I try to use a fillet surface fonction put it dosen’t work, it only do it on a side of a part

And also i made a loft with the circles here


But i can’t make a smooth curve with the circle part. normaly in the loft function you can tick the box “match start or end tangent” but here it is not available. do you know how I could make it math them together so that I it doesn’t look angular?


#14

I’m not following where you are trying to make a fillet. Did you cap the bell and now you are trying to fillet between the cap and the bell surface? If that is what isn’t working it probably is because the fillet radius is too big to handle the curvature of the bell.

In order to get the loft tangent option your first or last curve has to be a surface edge. The easiest way to do that is pick the curves (in correct order) after starting the loft command. You can also use MatchSrf command to make it tangent after you make the loft.