# Is this correct perspective?

In the image below, I have illustrated the interior of a bedroom with a slanted wall. On the slanted wall, I want to add a poster. Did I correctly use perspective here? Basically, I picked a point on the horizon that matched the top part of that slanted wall and used the same point to match the top of the poster.

Using the room itself, it would not be correct. Since there are two angles to use within the room, using those would provide more accurate perspective based upon the existing angles in the room (that I can see).

I have no idea how the horizon in your image was determined. There may be other aspects outside your posted image which warranted horizon placement. It is not impossible that you have the correct perspective if some factor merited the horizon placement where you have it.

• In my actual image, the horizon is much lower, actually. I just made it a bit higher in my sample image for demo purposes. But, in your edited image, would it matter if the horizon was lower since the two angles intersect above the horizon anyway? It doesn't seem the horizon matters at all from what you've shown me here.
– Desi
Dec 29, 2019 at 9:38
• What is determining the horizon? What's outside the window? If that's the case, then it doesn't matter. The room has perspective in it (via the 2 ceiling angles).. that should take precedence. What's outside the window is not relevant to what is seen in the room itself. Outside the window will change based upon being on the first floor or second floor, etc.. that won't alter the perspective seen in the room. The focal distance is the room.. since that is what is in perspective already. You can test this with more exploratory lines from the floor if possible. Dec 29, 2019 at 10:07
• @Desi -- See above comment (I forgot to ping you in the response) Dec 29, 2019 at 10:14
• I appreciate your help but I think it'd probably better if I show you the actual full sketch. Here is the link: i.imgur.com/smVkPzt.jpg The red line is the horizon. There are two angled walls and I'm trying to align the poster to the angled wall on the left.
– Desi
Dec 29, 2019 at 10:37
• @Desi That helps. Then yes you'd use the horizon... which is determined by following all the angles on the right to where they meet... then using that one left angle from the ceiling to the horizon, you get a point to reference from. Pretty much as you did in the question... [see here]( i.stack.imgur.com/sh3Qk.png) So yes you were correct in the question -- it was merely difficult to be definitive with the sample image only. (although that top right ceiling angle may be slightly incorrect as well.) Dec 29, 2019 at 18:58