The smaller the number, the more facets will be generated. The values are stored in the drawing file, so each file can be different.ĪECFACETDEV sets the maximum distance from the midpoint of a facet perpendicular to the true curve. The best you can do is make the facets small enough to give the appearance of a smooth curve.Īs you can control the number of facets that are generated using the AECVFACETDEV and AECFACETMAX system variables. AEC Objects with "curves" will always be approximated with facets. (princ "Select solids, surfaces, and regions to subtract from. (defun c:SUBTRACT2D ( / subtractfrom subtraction i ent extlength newpoint) (command "MOVE" (ssget "_L") "" "" newpoint) (setq newpoint (list 0 0 (/ extlength -2))) (command "EXTRUDE" pause "" (setq extlength (atof (getstring T "\nEnter extrusion length")))) Note that EXTRUDEBOTHSIDES was built in the process of building SUBTRACT2D which is also attached if you're interested. If you or anyone else is looking for a solution to extrude from a mid plane I wrote this lisp program to enable you to do so. The very old acronym still appies in either program.GIGO! Having started my adult life as a machinist, I have a good appreciation for precision.ĭon't get me wrong, Inventor is a far superior product, but AutoCAD is still quite capable in the right hands. I've seen a lot of folks that don't, though.Īs to the number of steps.2 extrudes or 1 extrude and 1 move.not a big difference to me, but I've been doing it a very long time. Fortunately, I know how to use the keyboard to enter the direction and distance to move things accurately. I run into the "garbage" as you called it all the time. The person who doesn't show work doesn't think it is necessary and thinks it is faster to take shortcuts. Kind of like a school math problem where one student shows his work while the other doesn't. With modern CAD programs not only are there fewer steps that reduce the likelyhood of unintended errors, but also there is a complete history to examine and determine everything was done correctly. And with AutoCAD - no history to see where the user went wrong.ĩ0% of what I see is garbage where users eyeballed the move or something similar. In my experience every extra step introduces a chance of error. These features (3 symmetrical extrudes, 1 symmetrical extrude-cut, one extrude and two revolves) all from profiles on the same plane All of this is fully paramtric - the model is driven by dimensions, not the other way around. Notice that I didn't even bother to trim some of the 2D. Nearly the entire part can be made from these with no change in "UCS" (I put in quotes as UCS as understood by AutoCAD users is seldom used in modern CAD programs). Here are a bunch of 2D profiles on the xy plane. I teach Inventor, SolidWork and Pro/E (Creo) using the BORN Technique (Base Orphan Reference Node) where as much as possible everything comes from the origin workplanes (xy, xz, yz) for the robust models that are easy to edit and less likely to fail on edit. Modern CAD programs allow midplane extrusions which are very useful. No - AutoCAD extrudes in one direction either + or - from profile. Any single extrude operation is symmetrical anyway. I really don't understand why this would be necessary anyway.
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