Basic overview, solid model design

[Chris333]

Something like that steeple in Sketchup. You could draw a circle and it will say 24 in the lower right box. That is how many segments the circle has. Select the circle tool and type in 8 and the circle will have 8 segments. Boom no angles to figure out.

[peteski]

Something like that steeple in Sketchup. You could draw a circle and it will say 24 in the lower right box. That is how many segments the circle has. Select the circle tool and type in 8 and the circle will have 8 segments. Boom no angles to figure out.

Now he tells me!    

It wasn't just the main spire. That was easy. I somehow managed to create the octagon base, and the rest was a breeze.  Come to think of it, I might have done it the way you described it.  My memory is fuzzy on that.

It was all the odd angles where the lower roof meets the spire, and where the dormers connect with the spire and with the lower roof.  There was some crazy stuff going on there. SketchUp made it much easier than trying to figure out the math on a piece of paper.  That's where 3D design shined for me.   Remember, I also had to create a flat design on paper for mark to cut out, fold and glue.

[daniel_leavitt2000]

Thanks for this!

I'll give it a try after I get back from Germany.

[learmoia]

Back in my day.. (only 20 years ago..) I had to spend $40,000 to go to college for 4 years to learn this..

~Ian

[Lemosteam]

If your CAD tool has the ability to create reference geometry (points lines and planes, and the ability to reflect and rotate, etc, I like to design only 1/4 of the geometry that is directly symmetrical about two planes, such as 1/2 and end wall, and its adjacent side to minimize the amount of detail that is required to actually model the whole car.  Then I create asymmetrical stuff like side doors end ladders and then rotate a duplicate around the central axis of the model, then the totally asymmetrical stuff that does not need to be duplicated (underbody stuff, etc) last.

[Maletrain]

One of the things that I have not seen mentioned in this thread is curved surfaces.  Is there a set of spheres, cylinders and cones already programmed into the tools?  And, more important, is there an ability to have the computer make surfaces that connect two non-straight, non-parallel lines, such as the  ends of off-set cylinders like we see in the transitions from boilers to smoke boxes on steam locomotives?

Those things seem easy enough to program into the tool, but hard to do "by hand" trying to draw on a computer screen.

[wcfn100]

And, more important, is there an ability to have the computer make surfaces that connect two non-straight, non-parallel lines, such as the  ends of off-set cylinders like we see in the transitions from boilers to smoke boxes on steam locomotives?

I don't know if or how all programs do this, but in the programs I use, this would be completed with a Loft tool.  I would assume most programs can do this, but years ago, this was one of the tools I would look for to see if a drawing program had all the tools I would need.


Jason

[Lemosteam]

One of the things that I have not seen mentioned in this thread is curved surfaces.  Is there a set of spheres, cylinders and cones already programmed into the tools?  And, more important, is there an ability to have the computer make surfaces that connect two non-straight, non-parallel lines, such as the  ends of off-set cylinders like we see in the transitions from boilers to smoke boxes on steam locomotives?

Those things seem easy enough to program into the tool, but hard to do "by hand" trying to draw on a computer screen.

This is one of the reasons I always suggest Solidworks.  It is difficult to use a solid to create complex curved surfaces and have them look smooth in some highly complex surfaces.  Higher end CAD tools have a huge range of surface development tools to manage compound curvatures such as rthe prow of the 3768, etc.:

[Sumner]

......... more important, is there an ability to have the computer make surfaces that connect two non-straight, non-parallel lines, such as the  ends of off-set cylinders like we see in the transitions from boilers to smoke boxes on steam locomotives?.....

Thanks for asking and....

I don't know if or how all programs do this, but in the programs I use, this would be completed with a Loft tool.  I would assume most programs can do this, but years ago, this was one of the tools I would look for to see if a drawing program had all the tools I would need....  Jason

Jason thanks for answering.  A 30 second search and I found a new tool ....

... that I'll be using.  I doubt that I'm even using 10% of what Fusion has to offer and all for free in my case 

Sumner

[bbussey]

I use either a loft or revolve, depends on the situation. I also use domes for smaller requirements, such as the taillights and running lights on trainers. I use revolve for master rivets, with the sketch plane in N being the body surface and inset 20% of the diameter in HO. Complex passenger car roof ends is one area I would use a loft feature.

[samusi01]

@Sumner

I'd also recommend learning about the form tool (that purple cube on the toolbar, Design workspace, solid). There are areas where lofting won't work that well and using a form or sculpting may be the solution.

Sam

[nickelplate759]

... And, more important, is there an ability to have the computer make surfaces that connect two non-straight, non-parallel lines, such as the  ends of off-set cylinders like we see in the transitions from boilers to smoke boxes on steam locomotives?

Those things seem easy enough to program into the tool, but hard to do "by hand" trying to draw on a computer screen.

Those complex surfaces are often modeled with something called NURBS - Non-Uniform Rational B-Splines.
I'm NOT making this up you know!   https://en.wikipedia.org/wiki/Non-uniform_rational_B-spline#:~:text=Non%2Duniform%20rational%20basis%20spline,mathematical%20formulae)%20and%20modeled%20shapes.

[Sumner]

@Sumner

I'd also recommend learning about the form tool (that purple cube on the toolbar, Design workspace, solid). There are areas where lofting won't work that well and using a form or sculpting may be the solution.

Sam

Thanks,  I just looked at a video ...

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Interesting.  Might be useful at some point,

Sumner

[wcfn100]

Those complex surfaces are often modeled with something called NURBS - Non-Uniform Rational B-Splines.
I'm NOT making this up you know! 

When NURBS were introduced into 3D Studio Max in the 90's it was a game changer for sure.  It should be noted however that NURBS are for splines and surfaces.  I don't know how they factor into the solids modeling programs of today.


Jason

[nickelplate759]

They're likely being used by the CAD program behind the curtain, without you having to explicitly manipulate them.