Lofting issue - "Selected cross section is not valid. 1 found 1 was filtered out, 0 total"

[kratzmike]

Ok...So I am as green as they get when it comes to AutoCad as I've just started trying to learn it from YouTube videos.  To give you an idea of my skill level...I'm sad to say that the attached dwg, while simplistic, took me 5-6 hours to extend, slice, rotate, scale, and properly align, so please bear with me if my question seems idiotic.

I have a 3DSolid that I've made copies of and have scaled versions 2 & 3 down further and further.  I would like to now Loft them all together, into a single object, that ends up Lofting into a sphere.  

Can someone point me in the right direction to figure out why I can't Loft 3 identical objects into one and then Lofting that into a spheere?

TIA.

[leeminardi]

It looks like you want to loft straight between the 6 sections.  Is your goal a shape like that shown below? If so you should loft 2 sections at a time.

Start by exploding the 3 solids in your file.  I'll assume the bottom section is #1 and the top section (inside the sphere) is #6. After exploding the solids the top and bottom of each is now a region. Enter the loft command and click on section #2.

Now hold down the shift key and press down on the scroll wheel of the mouse and rotate the view so you can see section #3 and pick it. 

Hit Enter twice and you should have this.

Similarly, create a loft between sections #4 and #5.

To make a single solid from the shape you can use surfsculpt. When I tried to use it on the model I got an error that the volume was not watertight.  I suspect there is a problem with how some of the side surface meet with the region sections so I create plane at each section and used them with surfsculpt.

After converting the five segments to solids use union to make combine them and the solid sphere into one solid object.

A side note, note that the lofted surface between the 4th and 5th sections have an undesirable twist.  This can be  caused by inconsistent starting points for the sections.  It is best practice to make each section's outline go in the same direction and start at the same relative location. 

[fatal.error · Accepted solution]

Please follow these steps:

1. Select the Bottom 3D Solid's Top Face by holding CTRL while clicking on that face.

2. To rotate the view and see Middle 3D Solid's Bottom Face, hold Shift key while clicking on middle button.

3. Select the Middle 3D Solid's Bottom Face by holding CTRL while clicking on that face.

4. Type LOFT command and hit Enter.

5. Repeat the same steps on the next 3D Solids.

Please see thea attahced result.

[kratzmike]

Thanks...That actually worked...I did not know I had to use the Ctrl key in conjunction with the selection of the surfaces.

So...Next newbie question...What does AutoCad do differently when you Ctrl+MouseClick (the 2 surfaces) and just selecting the 2 surfaces with just a mouse click, and then issuing the Loft command?  What does the Ctrl do for you, other than making the Loft command work?

[fatal.error · Accepted solution]

You can use the following objects and subobjects with LOFT command:

Objects That Can Be Used as Cross Sections	Objects That Can Be Used as a Loft Path	Objects That Can Be Used as Guides
2D polyline	Spline	2D spline
2D solid
2D spline	Helix	3D spline
Arc	Arc	Arc
Circle	Circle	2D polyline Note: 2D polylines can be used as guides if they contain only 1 segment.
Edge sub-objects	Edge subobjects	Edge subobjects
Ellipse	Ellipse	3D polyline
Elliptical arc	Elliptical arc	Elliptical arc
Helix	2D polyline
Line	Line	Line
Planar or non-planar face of solid
Planar or non-planar surface
Points (first and last cross section only)	3D polyline
Region
Trace

By plain-cliking the object, you select the entire 3D Solid (not a valid LOFT input).

By ctrl-clicking the object, you select only the surface behind the cursor/crosshair (Subobject Selection).

In addition, you can control-click on Solid Edge (blue) or Solid Vertex (red):

Furthermore, if you turn to the 3D Basics or 3D Modelling workspaces (bottom right gear icon), you'll find the Selection Ribbon Panel.

Select the desired Suboject filter and use any of the Window, Clossing Polygon, Fence or Lasso Selection methods without holding the CTRL key.