Dimension tool won't grab a wall

i’m trying to use the dimension tool to display the distance across a room. on the east wall, lets say, i pick a corner to grab in a doorway, that is mid-wall, then come across to a point on the west wall. however, on the west wall there is no corner, just the solid wall. the dimension tool won’t always grab that west wall.

if i try to grab the west wall first, then it wants to take the measurement of the west wall itself. the north/south length. what am i missing here?

thanks for the help.
cheers, md

In order to pull a dimension, there must be a point to dimension to {or grab as you say). Without actually seeing your example, I am surmising that you are trying to dimension to some undefined point on your west wall, but no node or point exists to establish a linear dimensional reference from your point of origin. (It’s always good to include either an image or the skp file.)

The simple fix is to establish an arbitrary point for your dimension string to occur, so just strike a line at the desired distance away from the doorway jamb corner, pull your dimension string to that point, and then simply either erase the line or put the line on a layer that you can then toggle the visibility to off.

(Bear in mind though that it is not good form in SU to place raw geometry on any layer other than Layer 0 so)…If this is a condition that occurs repeatedly, you may consider placing the arbitrary lines within a group, situating that group on a specific layer and toggling that layer between on or off as needed for performing your dimensioning operations.

Also, recognize that you can dimension to the face at the top edge or bottom edge of your wall and you may locate reference points for dimensioning more easily. It should always be possible to dimension the width or length of an enclosed space.

SU’s dimensioning tool is not exactly a Rhodes Scholar, but it is smart enough to know that you want a dimension in a normal direction rather than at some arbitrary angle. Accordingly, the two points do not have to be directly across from each other: SU actually constructs extension lines to transfer the point location to a place where it can measure straight across to the other point, which may also sprout an extension line.

In the following picture notice the two endpoints that are lit up in green–on the door opening and the end of the room on the floor. Those are the points I selected to represent the distance across the room.


I ran into the same problem (with SU for iPad) and thought of adding a line or point to anchor to, though that seems a bit of a kludge. What I did find works is dragging out a guideline that runs from the starting point to the target wall. Where the guideline crosses your target wall is where the dimensioning tool will grab, and the reference line shows you exactly where your dimensions are taken. Then erase.

Perhaps the dimensioning tool could have an option saying “hey, I’m not measuring an object, I’m measuring a space”, and include axis selection too, just to give it a bit more to go on? It just seems to fail the “intuitive” test right now.

You might try searching for a plugin that can add a single construction point by placing the cursor near an edge then left-clicking the mouse and use it for dimension snapping point.

Try searching the 3D Warehouse, SketchUcation, or Smustard. I have used one for at least 10+ years primarily for the reason you posted. I assigned the plugin as a shortcut for the “period - del” key when numlock is toggled on. You can put the c-point to specific TAG/Layer to hide or delete them, manually hide them, or just do an “Edit > Delete Guides” when you have finalized your mode.