topic Complex Sketch - Slow Model! in Inventor Forum

Complex Sketch - Slow Model!

paulZKN98 — Fri, 24 Oct 2025 16:53:50 GMT

Hello CAD world,

I have a model that I'm fearing will turn into major time drain.

The model will the the skeleton for a Frame generator assembly. The skeleton is of a handrail that will have diagonal pickets, however the rail is following curves and has no straight edges.

I've built the current 3d sketch off of a 3d point cloud, using a 2d base spline. I aim to use both the 3d and 2d sketches in the frame generator assembly. The diagonal pickets are dimensioned off each other and constrained to the projected 2d sketches. As far as I know, there's no way to pattern a 3d sketch element - otherwise I'd just pattern along the splines.

The problem now is I'm only 1/4 of the way done and each dimension takes about 30-50 seconds!

Can anyone offer any suggestions on how to reduce the load or simplify the model to increase speeds?

Many many thanks

Paul

Re: Complex Sketch - Slow Model!

swalton — Fri, 24 Oct 2025 17:28:10 GMT

Are the individual pickets identical as they follow the curves? If so, just make one sketch for frame generator and use the Assembly pattern tools to build out the rest.

If there are a few different picket shapes, try making a sketch for each one, then using the pattern tools as above.

You could also break up the picket sketch into several smaller sketches. I try to limit sketches to 50-100 individual geometric entities.

Do the spacing of the start and end points of the picket lines need to follow the arc length or the chord length along the splines? If the arc length is allowable, try using a workpoint pattern that follows the spline. Project those points into the picket sketch and link them with lines. That will reduce the dimensions that Inventor has to display and calculate.

Re: Complex Sketch - Slow Model!

paulZKN98 — Fri, 24 Oct 2025 18:59:00 GMT

Steve - thankyou for your thoughtful suggestions.

My solution may be a combination of all of the above, the patterning feature may be the best route.

The workflow is clunky - I have to make a feature in a part then make a feature driven pattern in the assembly. I'll need to wrestle with this because it appears that the patterned part must be at the same location as the patterned feature. I'll have to play around with it.

The first go at it worked well enough, I'm going to fiddle with the start location and make these centered about the middle of the spline.

Thankyou again!