How to make lines visible above an image?

tiptongrange

I imported a jpeg of a plat map and am trying to trace the outline of the site. However, the lines that I draw are not visible from above the image, they are only visible from underneath. What's happening and how do I reverse this?

solo

Got an image for reference?

d12dozr

If I understand what you are asking correctly, you can explode the image (if necessary) and reduce its opacity in the material editor to about 30-40%, then you will be able to see the lines you draw in Sketchup.

tiptongrange

@solo said:

Got an image for reference?

Here's an example of the problem. When the 02-Plat Map and 03-Site Outline layers are turned on, you can see the outline of the site if you tilt to look from underneath, but you can't see it from above. How do I reverse this?

The odd thing is that this happens only when I import the Google Earth image first, then import and drag and stretch the plat map on top of it afterwards. If I just import the plat map by itself, then drawing on top of it works fine.

Example.skp

Gaieus

Hi TTR,

Have a look at this file. I turned it into parallel projection and saw you were in X-ray mode so I turned that off (X-ray mode is typically the mode where you can pick things "behind" a face and this makes drawing on a face difficult).

Now I drew a big rectangle with the exact size as your image has (included your first rectangle you drew) and moved the whole thing up by 50' (you can move the whole thing back later.) I painted it with a single colour and made this colour somewhat transparent (instead of X-ray mode - see reason above)

Viewing this from top view in parallel projection will allow you to draw "On face" (it will display a dark blue inference point all the time) keeping your drawing in that plane but enabling you to see the image below. Image entities will not turn "transparent" in X-ray mode.

Be careful NOT to orbit but only to pan (and zoom in/out). To make sure you can always go back to this view, I made a scene tab, too.

Example.skp
This method is actually quite good to trace lines of curved surfaces below.

Update; I "played around" with it a bit further and those big blobs are placed quite well so when you draw the straight edges first, you can use the arc tool to fill the curved "corners" and rely on the cyan tangent inference.

Also I modified the style for you to see where your endpoints are for the time being.

tiptongrange

I'm not quite sure what you did. This is what I tried in order to replicate what you explained.

Traced a rectangle around the original image
Raised it 50' above the ground
Painted it a single color with 0% opacity
Turned to top view in parallel projection
Traced the outline of the property line
Lowered everything back to ground level

After doing this, the outline of the property line still shows on the underside of the image instead of on top of it. Is this what you did?
(Also, I never had this in x-ray view.)

tiptongrange

@d12dozr said:

If I understand what you are asking correctly, you can explode the image (if necessary) and reduce its opacity in the material editor to about 30-40%, then you will be able to see the lines you draw in Sketchup.

Thanks for the response. But, I'm looking to understand why lines that I draw will show on the top side of some images and on the underside of others. I'd like to know how to control this.

Gaieus

Well, when I opened your file, it seemed to be in X-ray for me (maybe it was me who turned it on only?)
As for image entities; yes, in the latest version(s?) of SU they appear in front (on top) of a face they are placed on and even without Z-fighting. This can have several advantages even if it may be disadvantageous sometimes.
Anyway, after you traced everything on your raised face, why not just hide (or even delete) the image entity? You do not really need it any more. Or you can even explode it and the image will become the texture of your site plan drawing that way.

brookefox

XRay mode seems to be a good 'solution' to a problem resulting from trying to get coincident 2d surfaces to behave in a very precise way when by definition they may not be able to: one on top when there is actually no top even if sometimes it seems like there is, or at least that's how it seems to me. But with the X Ray you can see and snap to your drawn lines on the back side of the image. Does drawing in XRay allow you to do what you want to do?