Quadripartite Vault

Think i may have solved the thickness issue - looking at the model in plan and zooming in on the centre arc shows the bottom edges of the solid diverging, this means the thickness is increasing as the slice isn't vertical, rather it is at an angle. Will confirm this when i move the project onto the next phase (designing the formwork underneath the model) - but i am beginning to think that CAD has done what i asked all along, i just interpreted it incorrectly.

OK, next issue...

I am taking slices of my model at regular intervals in order to draw the supporting structure beneath. However, one of my elements will not slice.

All of them are now 3D solids, some produced using loft and some produced using extrude.

QUOTE: Modeling Operation Error:

Attempt to fit curve to zero or one points.

SLICE failed for selected solid.

Any ideas?

----------------

Update:

Managed to break the element by drawing a square and extruding it through it and then using subtract to split it into two halves, however both halves appear to be one object still (very bizarre!)

Also it won't let me explode it.

As far as AutoCAD is concerned they are one. Just because there is an empty space between the objects doesn't mean they are individual objects. Use the Separate command to break the bond that holds them together.

Hmmm...

QUOTE: Command: separate

Unknown command "SEPARATE". Press F1 for help.

I am using AutoCAD 2007 (not LT) - is this a newer command?

Hmmm...

 

QUOTE: Command: separate

Unknown command "SEPARATE". Press F1 for help.

 

I am using AutoCAD 2007 (not LT) - is this a newer command?

No, you shouldd find it in ACAD 2007, Modify>Solids Editing>Seperate

Found it - much appreciated

... it doesn’t have the ability to stitch together individual surfaces...

Not needed in 2011. Sculpt command will "flood fill" enclosed volumes.

Not needed in 2011. Sculpt command will "flood fill" enclosed volumes.

That’s good to know. I may even get a chance to give it a try in the semi-near future . . . . if all the budgeting efforts pan out. Have you been able to determine if it is significantly more competent than the geometry illustrated in that help blurb?

With regard to the “... it doesn’t have the ability to stitch together individual surfaces...” statement; that definitely applies to AutoCAD 2007 (OP’s version).

Update...

Managed to get the first segment working, have sliced it up and created my supporting formwork ribs, the model currently looks like this:

Some extensive timber detailing going on, especially at the apex, check out this quick render...

So, not going too badly today, thanks to you guys and your help so far.

Next step is to fill the last segment with a 35mm thick solid and then slice it up and design the supporting timbers. Finally i need to take the ribs and then produce shop drawings for manufacture.

Struggling with loft again...

I am posting the geometry of the other surface, hopefully someone will be able to look at it and let me know what i am doing wrong. Error message is as follows:

Command: loft

Select cross-sections in lofting order: 1 found

Select cross-sections in lofting order: 1 found, 2 total

Select cross-sections in lofting order:

Enter an option [Guides/Path/Cross-sections only] : g

Select guide curves:1 found

Select guide curves:

The selected entities are not valid.

I have checked the guide curve, it is a polyline and the ends look to be in the right places (ie corner to corner of the two shapes) - i can loft one into the other without the guide curve so i am thinking the curve is at fault, but can't seem to find out what the problem is. Doesn't work with the Path option either.

Can anyone help?

I think that if i can crack this last issue, i should be able to complete the project

surface2.dwg

I think part of the problem is that the cross section is tangent to the elliptical path at the ground point. Ideally, it would be perpendicular - like it is at the apogee.

Makes sense - will give it a go and report back...

Success!

Next steps are to slice it up and produce the formwork - will update you as i progress - thanks again for all your help so far.

OK, for some reason the new shape wont slice...

-------------------------------

Command: _slice

Select objects to slice: 1 found

Select objects to slice:

Specify start point of slicing plane or [planar

Object/Surface/Zaxis/View/XY/YZ/ZX/3points] :

Specify second point on plane:

Specify a point on desired side or [keep Both sides] :

The Boolean operation on solids failed.

Modeling Operation Error:

Inconsistent face-body relationships.

SLICE failed for selected solid.

-------------------------------

Any ideas?

OK, have some weird things going on...

The cyan solid wont slice at all - this is a deal breaker i think, unless i can slice it up i can't get the top profile of the formwork ribs below. The ultimate goal is to produce ribs to match the profile of the new solid, like i have done for the other one:

Even more bizarrely, the black slice lines work on both the brown MDF ribs below, the purple ones work on the far rib only! I can slice the closest rib, but only up to a point, then it fails. There is one slice line that works in the middle of the ones that don't too - very odd.

I confess to being very puzzled here...

Had a go at redefining the solid using different sides, managed to succeed thus:

But this new solid also won't slice either... There seems to be something fundamentally wrong somewhere.

Just been playing around with it and got an error message while trying to use the shell function (for no real reason, i'm clutching at straws a bit here, probably a red herring) - Free edge detected.

Could this be the reason it won't slice? If so how do i resolve this?

Redefined the shape for a third time - just to cover all the bases. Have now lofted the shape using all three combinations of the sides - again, shape will not slice - gives the same error message:

Modeling Operation Error:

Inconsistent face-body relationships.

SLICE failed for selected solid.

Seem to have wasted my entire day with this

Think i may have cracked the big issue - had a good close look at all the solids i have been making today (i kept them all) and following on from the last error message (the free edge one) i found the following issues...

All three of them had edges that didn't meet 100% (in the case of the last one the issue was tiny).

Had to tweak the defining shape a little (adjusted the bottom edge - i will re-set this out offsetting from the top edge when i design the supporting ribs) and then lofted the shape again and now it slices!

Think i can now finish the project - the non-slicing side rib is still a problem, but i think i can get round this (fingers crossed).

Lesson of the day

Accuracy in 3D CAD is much more important than in 2D CAD!

It has taken me all day, but this lesson has been very much learned today...

Update...

Think i'm done

All formwork now designed in 3D, now i need to produce manufacturing drawings in 2D of each of the timber ribs.

Thanks again for all your help - very much appreciated.