Driven dimensions

[ibethel333]

I have a sketch that is made up from parametric dimensions. There are some reference dimensions (driven dimensions) that i need to update other areas of my sketch with. This all works until i change one of the dimensions in the parameter list. It throws up an error and will not update the sketch saying that the dimension is invalid. If i delete this dimension, the sketch turns blue and i am allowed to manually move the sketch to a different dimension,  but as soon as i try to add the dimension to a differnet size the error comes up again? this used to work on this file after the driven dimensions being allowed to be used as references was introduced. has one of the recent updates stopped this function from working?

[g-andresen]

Hi,

Driven dimensions can only be used in equations within the same sketch.

Please share the file.

File > export > save as f3d on local drive  > attach it to the next post.

günther

[ibethel333]

Hello Gunther

Please find attached file. If you go into the parameters list and try to change the WidthBase dimension, this brings up the error. But if you delete the dimension 1016 in sketch1 then most of the sketch goes blue and it lets you move the shape outwards or inwards until you add the parameter to the dimension again?

[ibethel333]

I forgot to add. I use this sketch as a development for dog boxes that we manufacture from a sheet of polypropylene 6mm thick which works like a wrap, so there is no machining files as i export the files as a dxf to  a different software to run my router (Vectric Vcarve Pro).

[ibethel333]

If a solution cannot be found i will just add the dimensions manualy like i did before driven dimensions could be used as i need them. I have been using this method succesfully for a few years now.

[laughingcreek]

I don't see a driven dimension being used in sketch 1.

I see D2=WidthBase=1016, but that's not a driven dimension.

The only driven dim I see is D184=621.6, but I don't see it being used anywhere else.

I suspect the liberal use of the mirror constraint is the issue here.  mirror in sketches has always been problematic, and it's usually advised to avoid when possible.  After deleting D2, it's still difficult to drag the top (now blue) line, indicating that the sketch solver is struggling.

I imagine you put D2 in place fairly early on when making the sketch.  Now that the sketch is complete, the solver is happy as long as you don't change the dim, but causes conflicts when you try to change it (ie, the solver got boxed into a corner)

since the sketch is (mostly) symmetrical top to bottom, it will be behave better if you modeled half of it, then mirrored the extruded solid instead.

[ibethel333 · Accepted solution]

Hello Laughingcreek

I know my sketch is asking a lot of the processor, i was just hoping it was a bug. It has worked in the past until recent updates. I think i will just simplify my sketches as you say and see if that works better. I have used the symetry constraint a lot which on reflection makes it a mirror comand, so i will have to get used to not using this constraint as much lol. I have about 30 similar programs for different models of boxes we make. nice project for over the Christmas period, sorting them all out.

Thanks for the quick reply

Regards

Ian