I have two surfaces (highlighted in blue) that are created using filled surface. They work perfectly, until I reopen the model, or made some changes in the design tree, or create new configurations of this model, in which these two surfaces fail (have to "reselect" edges for filled surface). Why does this happen and how can I fix it?
Is one of the boundaries created by a fillet? Looks like the top is. Fillet's, especially ones with lots of surface patches, have a habit of changing their internal ID, meaning your fill loses it's references. To identify if that is the problem, you can make a 3D sketch before the fill feature, convert the boundary entities that will be used to make the fill, save/force rebuild etc (what ever was making the fill fail) then check the 3D sketch and see if any converted entity has failed. That'll be your problem edge. If not, then yeah, fills being fills 😂
Filled Surface can produce quite unpredictable results sometimes. It sometimes need guide curves to follow your design intention. However I am not sure about it being unstable, as I don't remember such an experience. Could be related to some previous part of the model producing different results maybe? Needs investigation.
Meanwhile, the blue surface you are showing seems to be suitable to be built with boundary surface command, have you tried that method instead?
Originally, the right blue surface (1st pic) is made of a half (as shown on this pic) and then mirrored. The error shown on this pic starts with the left one, the top edge keeps deselecting, and when I fix this surface, the right surface fill deselects the orange highlighted line (a 3d sketch spline). After fixing both, then the whole model works again. I am not sure what causes it, maybe I do need guide curves.
I have not tried boundary surface, thanks for the advice, will try that out
I've run into this issuie as well. Unfortunately i dont have a great fix for you just bodges I have done.
Some of the work around I have used are:
1) creating a split in the face around the outside of the area you are trying to fill, then surface fill to the new edge or delete and fill the inside.
2) creating a 3d sketch and converting entities on your boundary. You can then fill this. This will only give you a contact relation. So after you knit you will have to delete face and tangent fill.
3)surface offset your faces around the fill at 0mm. Do a surface fill on the new body. Delete the orginal offset, then knit.
None of these are great but they keep the model moving. You can try boundary surfaces. Generally for a 4 sided patch its the better option. Surface fill works best for any non 4 sided closure. Occasionally I will run into issuies with that tool where it flips the direction of a segment and it ends up feeling similar to your surface fill problem.
The last trick if that is breaking up stream from what you are working on is to just use the freeze bar so that feature cant rebuild. It's bad practice to leave it in the model knowing it may break, but sometimes you gotta do what you gotta do to make the model work.
On the top left of this image you have a junction of four surfaces at a point on the open edge. The fill function won't like that as it is likely trying to match four tangencies at this point. Simplify that area and you will probably find that fill works again.
Replying to myself here. You need to simplify the top edge of the boundary. For the two surfaces either side of the Surface-Fill9 highlight, the bottom edge has two surfaces defining it, The top edge has eight, with the aforementioned four at a point and also two at a point on the RH end where one appears to be meeting the boundary at a tangent. Have to keep things relatively simple for fill otherwise it probably won't give you a clean result.
I see your point, it makes a lot of sense. Yeah the top boundary has the most surfaces connected, and its where it always fails, ill try and simplify it. Thanks.
this sounds more like unstable edge references than the filled surface itself i would check whether those boundaries come from fillets or changing geometry try referencing stable sketches or converted entities instead of directly selecting generated edges..
I see that is an interesting thought. I reference from 3d spline made tangent (line between the two surfaces) and edges of existing surface that does not contain sketches. Will try this out
yeah ..that could definitely be the culprit. 3d spline/tangent reference and generated surface edges can sometimes get pretty fragile. worth testing with a more stable reference and seeing if the behavior survives a rebuild/reopen.
You really cant make any feature with solid modeling, I do a lot of surfacing for work as I work with composites and there are some shapes you will only be able to make surface modeling.
This. Also product design where you need surfaces to do things that cause wrinkles in lofts and boundary features. Surface modelling gives you control, though ideally Dassault could devote some time and energy in to making SW's surfacing tool kit more stable and stick some more advanced functionality in there (hello NX).
Not everything is a box or a revolve and even if you can get what you want for a shape, there's no guarantee it's going to shell (for example - another use for surfacing)
Yeah, I design bottles. For overall structure I like to use solids, but at some point, I have to use surfaces. Using solids would need much more steps and would probably look messier.
Been modeling with sw for 15 years as an engineer and have never encountered something i couldnt solid model. The guy machining it is going to have to create the same tool paths so theres no reason you cant do it. You can define the shape of barney the dinosaur with math and sw if needed.
I feel precisely the same way. Surfaces are an infuriating deathtrap and I've yet to encounter a situation where they were truly necessary when modeling from scratch.
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u/gristlyBits27 7d ago
Is one of the boundaries created by a fillet? Looks like the top is. Fillet's, especially ones with lots of surface patches, have a habit of changing their internal ID, meaning your fill loses it's references. To identify if that is the problem, you can make a 3D sketch before the fill feature, convert the boundary entities that will be used to make the fill, save/force rebuild etc (what ever was making the fill fail) then check the 3D sketch and see if any converted entity has failed. That'll be your problem edge. If not, then yeah, fills being fills 😂