Force Inference

So, in Autocad I can easily choose to snap something to the Endpoint or Midpoint of a line, even if that point is WAY THE HECK OFF SCREEN, and the thing will go to that End or Mid or whatever.

SU makes me zoom in and out and ‘feel’ around a line until I touch the midpoint before I am allowed to make a thing go to it. In a crowded model and a perspective view, it can be hard to get a clear shot at an Endpoint or know where to hover on a line to get the Midpoint inference.

SU should have some sort of modal toggle to FILTER inferencing to only one selected type at a time. In Autocad it’s ‘click the middle button’ and you get a little menu of 8 or so OSNAP options.



I haven’t had any issues with snapping on SU but it could be nice to deactivate the snapping some times or choose what snapping points I would like to activate, also make that the length interval isn’t activated by default for new users.

If you can’t see what you are inferencing and don’t interact with it at all, how would SketchUp know what to try and inference with, especially in a crowded model?

If you could filter to ONLY MIDPOINT then click on any part of an edge to hit the MIDPOINT of that edge. This selection method has been standard in Autocad for DECADES.

  • Endpoint
  • Midpoint
  • Perpendicular
  • Extension
  • Tangent
  • Node
  • Mid-Between-2-Points

Lemme try and rephrase this so y’all maybe don’t flag it offensive (?!?!?)

Snap-to selection feature in Autocad has a functionality that is not present in Sketchup, and maybe a little hard to explain why it is so excellent to users who have not experienced it.

I think it could be implemented as an extension; and that it would be a thing that reasonably COULD be implemented into Sketchup main… for more so than my other pet peeve, TRUE CIRCLES AND ARCS, which I realize are never going to happen in this thing.

No 3D application displays true circles and arcs. All use some level of tessellation to display 3D surfaces or 2D shapes (AutoCad too has settings to determine the number of edges it uses to display circles). When you export from SketchUp to DWG, for instance, what you get are “true” circles and arcs. But SketchUp 3D geometry is face geometry, so those shapes will always consist of meshes with a predetermined number of flat faces.

it’s not about display, it’s about figuring geometry.

in autocad there are a lot of tricky geometric things i can figure out using arcs/circles in ways that are not possible in sketchup.

and also at a simpler level - if a circle doesn’t have a point directly on the orthogonal quadrant in sketchup that can really screw you up in trying to adjust its placement against other objects, requiring constant vigilance and fiddling

SketchUp, as its name shows, was first conceived as a quick and dirty 3D sketching tool. So for speed and efficiency it was based on polyface mesh type geometry. That about fixes it. A NURBS-based SketchUp would probably be a totally rewritten application. Who wouldn’t like that, but I don’t think it very likely to happen soon. There are other applications available (Rhino, SolidWorks…) that support that kind of geometric construction, at the cost of ease of use and a lot of money, too.

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I’m new to SU so everything is work for me. I have found that if I turn on x-ray I can snap objects to places “through” objects. That helps.

I agree that some things in autoCAD are easier, it’s the same with Chief Architect……they are miles ahead creating a layout file to print to PDF

I will be forever nagging about an experimental feature the developers demoed at the first ever SketchUp Basecamp when the application was developed by @Last Software. I wasn’t there but saw some of it on the Net. The feature was called Fat Faces and it added a thickness to faces. I still think it would have been great, especially for architecture.

The Shift+Right Click snap menu from Acad would be sooooo lovely.

I’m not an AutoCAD user and never have been, so I don’t know exactly how it works there. From your description, you have to right click first and then click again from a menu list? Can you do keyboard shortcuts for those?

I know PowerCADD and manually forcing snaps is a feature I’m use to there. It’s (almost) all done with single key shortcuts. Here’s what it has:

First there’s a floating read out of when a snap is succeeding or happening:
Screen Shot 2023-09-18 at 5.44.12 PM

They stand for
• Grid
• Vertex
• Align (like inferencing in SU)
• Intersection
• Surface
• Tangent
• Perpendicular
• Center
• End
• Percent
• Distance
• Offset.

In this example a vertex snap is happening. Grid and Vertex can be set to happen all the time automatically as a preference, but all the others you ask for by holding down the corresponding single key.

An advantage to the snap-on-demand approach is that the computer isn’t bogged down constantly hunting for snaps or inferences of all kinds all the time. With on-demand, it’s only hunting for one kind, and only while you ask for it. This is the kind of thing that might help Layout performance problems, perhaps.

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It works when in a drawing or modifying command/tool by holding the Shift button on the keyboard and right clicking with the mouse. That brings up a snap specific context menu which from there, the keyboard can be used to specify a specific snap - for example with that menu open, I can tap ‘M’ for midpoint. The menu used to underline the letters that correspond to the keyboard shortcut… Those have disappeared for some reason… Here I’m drawing lines and quickly selecting a tangent snap, endpoint snap, midpoint snap and a perpendicular.

Snap Context menu


This, 100%! :point_up_2:

there are several ways to do it; the middle button menu is easiest to explain but keyboard shortcuts are faster.

Thanks for the Explanation

Not that I don’t think it is a good idea, but I can absolutely draw to the mid point and end point of any line far faster than the time it takes in ACAD to select the options. With complex models, navigating is much easier when you have a well organized model with no free floating geometry and utilize hide rest of model with a single key command.

As for curves, yes that would be nice, but for architecture most in the field realize that just about every curve constructed is made up of segments… curved drywall tracks are a good example.

In AutoCad, too, it is customary to keep the most important “snaps” “running” and to use the one-off options only for rarely used things.
My SketchUp peeve is the several “from point” type inferences that can reference unseen and far away points. Oftentimes the slight movement caused by pressing the mouse button can cause the resulting point to jump away from the intended vertex to a nearby “from” point. So I would like a way to turn some of the more arcane inferences off. Turning it all off I think a very bad idea. I don’t know if it would have an influence on performance.

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I would definitely leave all of the snaps “on” all of the time or like @Anssi suggest, have the option to disable certain snaps. The right context menu is truly most useful when I want to snap to a specific reference, such as tangent, mid point between two points, perpendicular etc. I don’t think I or the OP are suggesting that the existing “auto snap” settings be changed. Only the quick option to force a particular snap.

Obviously this was slow for demonstration. In ACAD, with snap turned on, the end, mid, perpendicular etc… are on by default, and can be modified to suit any preference. The menu is is purely for forcing a specific snap.

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