failing SEO operator?

[Anonymous]

Hi to all,
This is a new problem to me, and my review of the forum didn't turn anything up.
My coworker was attempting to use a soffit (slab) to SEO subtract out a chunk of rafter (roof). After selecting the appropriate target and operator, and pressing "execute", the selection fields cleared (revert to zero), but nothing visually happened.
I moved the soffit and rafter down in the model, and voila! SEO action.
I left the rafter in the lowered position, and moved the soffit up until it failed to perform...please see the attached image.
I guess the soffit is interacting with something else in the model which prevents its functioning as an operator? I don't know.
Has anyone else experienced this? Any thoughts on what gives?
Thanks v. much,
John

[Barry Kelly]

Zobi wrote:
Hi to all,
This is a new problem to me, and my review of the forum didn't turn anything up.
My coworker was attempting to use a soffit (slab) to SEO subtract out a chunk of rafter (roof). After selecting the appropriate target and operator, and pressing "execute", the selection fields cleared (revert to zero), but nothing visually happened.
I moved the soffit and rafter down in the model, and voila! SEO action.
I left the rafter in the lowered position, and moved the soffit up until it failed to perform...please see the attached image.
I guess the soffit is interacting with something else in the model which prevents its functioning as an operator? I don't know.
Has anyone else experienced this? Any thoughts on what gives?
Thanks v. much,
John

I just had a similar problem trying to subtract slabs from a sloping beam for a stair (timber treads subtracted with upward extrusion from the sloping stringer).
Nothing happened until I moved the treads to be completey below the stringer - then the SEO appeared.
Move them back up and the SEO stopped working.
Exactly the opposite happened for downward extrusion - the slabs had to be completely above the beam.

I thought it must be something to do the the beams priority strength.
Changing this strength made no difference but putting the beam in a different layer to the slab worked.
But the layers must have different intersection priority numbers.

Barry.

[Anonymous]

Barry,
Bingo, exactly right. I changed to intersection priority of the soffit and pow! Perfect.
Thank you.
Still, I've not had to do that before, and I SEO my layers with the same priority numbers (roof and walls and stairs and floors, all on different layers) against one another all the time.
And why would it have worked earlier when in a different location?
Mysterious to me, but I'm grateful to have this as a solution.
Thanks again,
John

[cmacd]

I haven't played with with intersection priorities (but will try in future) but I have had many SEO problems that I have had to solve in a variety of ways.
I realise that SEO's are very complex but I'm still a bit frustrated that I have as many SEO problems as I do, particularly as it has had some time to 'mature'.
In one recent instance (v11), an L shaped slab with an arc extended out at the lower left corner refused to cut the terrain (mesh). Splitting the slab to separate the bottom leg fixed the problem (both slabs worked) (but why?) but now I have a slab line I don't want. In another instance, I created a ramp (roof) at a corner of the large basement carpark slab. The ramp would only cut the terrain if it was moved (incorrectly for dimensioning, etc.) a few mm away from the slab. In the past, I remember that adding one more SEO made previous SEO's fail. In all cases, the operator & target are on different layers.
SEO's are incredibly useful particularly if one tries to use the 3D model to generate all elevations, sections, model renders & presentations, etc., without using hiding fills and 2D lines. It would be wonderful not to have recurring problems.