Trying o model this base (pics included)

I lofted a circle of 4-1/8 and 3 and 1/2 inches above that, another one of about a half inch radius. The good news it it worked; to a point. Instead of coming out with a rounded top of the dome, it came out flat.

So as far as the dome is concerned, how do you get it to appear with that rounded top portion?

The gooseneck portion of the lamp: do you have to model in the ridges that make up the gooseneck or is that achieved through texuring/rendering?

Thanks.

TMC

Regarding the dome, could you not just draw half of the profile as seen from the side, and revolve it?

The twisted coil can actually be modeled as a 3D solid. I think one of the forum members has done something similar in the past and may even have posted the results. The HELIX command comes to mind.

If you need the top to be radiused, then using revolve is usually the way to go, and makes the shade easy. FYI you can make the loft terminate to a point, but it will not yield a true radius. The gooseneck is much more challenging, because it is not straight. In order to model that detail shape you need to create a spline based helix to be used as the SWEEP PATH. To the best of my knowledge you cannot do this with Autocad Vanilla. If you were able to do it, I believe that the SWEEP command would disallow it as it would create a self intersecting solid. A twisted coil is easier for that reason. Perhaps with Inventor there is a way to do it. I am loathe to say that it can't be done, but I would be interested to see how it was accomplished, should somebody know how to do it. ReMark may well be right, he usually is, but I don't believe that I ever saw it. That doesn't count for much though, as I am a newbie hereabouts, and thus lack the 'crust-factor' of many of the longtime Autocad abusers on the forum. I'll be interested to see if somebody knows how to model it, especially in Autocad. Good luck.

The twisted coil can actually be modeled as a 3D solid. I think one of the forum members has done something similar in the past and may even have posted the results. The HELIX command comes to mind.

Thanks for your reply; that was the first thing I tried. My research (that I did at the time) suggested that a helix can only go straight.

The definition of a helix would argue against that assumption.

I'm pretty sure you could do it with a spline too if you're careful with you point placement in 3D. But I'd opt for a helix first. Just my opinion. Feel free to ignore it.

Another option you might look into is the Array via Path. Maybe that would be easier?

You can get the effect using the array command and some slicing...

This was somewhat exaggerated but it shows the effect. Copy along a path would be a better option if the new command works in 3D? I have not tried 2012 as of yet:

The definition of a helix would argue against that assumption.

 

I'm pretty sure you could do it with a spline too if you're careful with you point placement in 3D. But I'd opt for a helix first. Just my opinion. Feel free to ignore it.

 

Another option you might look into is the Array via Path. Maybe that would be easier?

Thanks for correcting my inaccurate assumption; and for the ideas. I'll try them out.

TMC

I think ReMark was alluding to my description of a spline based helix, which as he correctly states would by definition, not be a helix, which must have a straight linear component as would be applied to a cylinder or a cone. It need not be perpendicular to the basepoint, but it will describe a straight path.

Short of a very labor intensive session of slice & dice with lots of union commands I don't see the native commands in Autocad doing this gooseneck justice. No doubt there is a way to do it with lisp and a lot of very advanced equations. There are those reading this who would know for sure.

kencaz has done a very nice job of creating the effect, but the spiraling feature of the gooseneck has been sacrificed or lost in translation.

.... I don't see the native commands in Autocad doing this gooseneck justice.

If the OP has access to Autodesk Inventor the gooseneck could be made with Helix and then Bend Part.

Students can download Inventor for free from http://www.autodesk.com/edcommunity

But for the sake of speed - I would use a cosmetic texture unless the detail is required.

By the time you back up a bit to see the whole lamp and a bit of the environment in a render - you wouldn't even be able to tell the difference between a cosmetic texture and modeled geometry.