Can someone help me on perspective for a cylinder object ?

2yr

Charline B.R.

I'm trying to exercise on perspective, a topic I avoided for years and I have trouble with how to calculate cylinder with a perfect round basis in a 2 points perspective.
The left tower in the back seems completly off. I tried multiple calculation but every time it's weird.
How do you calculate a perfect square on a 2 points perspective (which is what I tried to make my cylinder) ? The method I found looked correct but the result isn't convincing at all...
Any help or link would be appreciated :)

2yr

Hi! I'd be happy to help but can you tell me or show me approximately where you think your vanishing points are (the two on the sides and the central one, if you know it)? This will give me a better idea of the effect you're looking for.

Charline B.R.

2yr

One of the vanishing point is very off canvas, which is why I have so much difficulties. The other is below the gates, if you open the image in full size you will see blue-violin lines going to it with the horizon line.
But I don't understand what is the central point you mention ?

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To be able to construct a perfect square in perspective, you need to understand a little more perspective, so you can construct the vanishing points for the diagonals of the square. using a 'stationary point'. It goes too far to explain it here, but google is your friend. Let me know if you need help, and I will see if I can find some pointers.

2yr

I understand it was a bit too advanced for me, I tried to follow this tutorial : https://architecturerevived.com/how-to-draw-a-perfect-cube-in-perspective/
But I think I misanderstood it.
I will give another try when I have more mileage, I have some french castle I want to try :)

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2yr

Tear down the building at Right; Copy the tover-shape at right and place similar to the left towers place. Even if the buildings UNDER the towers are oval it will not effect the cylindrical shapes. Tower to the left might be slighlty smaller-- very litttle compared to the right tower as it in fact is a small bit away from your ount point , There shoulld be a perspective point far away to the left somewhere on the eye-point line. Pleace take no offence for me interfeering..

2yr

Oh, that could be a fast and efficient way to solve my issue, you are right !
But I need to reshape the base level too because it wasn't supposed to be oval, it's me confusing measure when drawing the construction cube. I need more practice with round objects...
Many thanks, I'm very glad you take time to show me what I can do :)

2yr

Hey Charline B.R. what a really nice drawing so far. The first thing i notice is that it seems to me like a one point perspective and not a two point perspective. All lines are pointing to one point (behind the right tower). Or is the other point really far to the left?
What i see on your left tower is that the top of the cone is not in the center of the base of the tower. A vertical line need to run from the center of tower cilinder and the cone tip and bottom circle need to lay on that center line. I found a youtube video showing the principle: https://youtu.be/zkIYARAJVIA
The roof of the tower is constructed of 2 cones that are overlapping, but both cones have their center on the vertical centerline. I hope my description is helping you in the right direction.

2yr

Many thanks for the video, I checked out quickly and it's a better way to position the roof than the goofy way I used.
Yes it's a 2 points perspective, I tried to replicate a city in a game, but with on scale buildings and human-sized props, which gave me a very wide lens. Again it's the first time I really try to do a correct perspective by hand so I may totally have done poorly in choosing such distance ^^"
Again many thanks for your time and explaination !

2yr

So I did a quick drawover of the scene in photoshop. A couple things I think you should note.
First is the concept of drawing through. The ellipse on the bottom is the tower looks quite off, and that is because you are not drawing the entire shape, just the front of it, as a result, the ellipse comes off quite flat. Another thing to remember is that ellipse(and flat planes aswell, will get fatter the further they get from the horizon line. I did a quick chart on the side to illustrate what I mean.
Second is to block out the shapes. Start with a basic cube, and then draw an ellipse inside. When you have it blocked out, it follows the correct perspective. Your tower sort of melts away because it lacks the correct structure that the rest of your buildings have.
Finally try and find the centerpoint of shape. The best way is to do an x from the corners of the bottom plane(in a cube) and the center of that x is the middle. There you can draw a straight vertical line and find the point of your cone.
If you have any questions or need me to clarify, feel free to ask.
The drawing is looking really good by the way. Looking forward to seeing the finished piece :)

2yr

Thanks for the words of encouragement :) and many thanks for the redraw !
Yes I see what you mean, I did used cube to draw my cilinders but I messed poorly with the result.
I used a way to "calculate" a real square in a 2 point perspective, sadly I think I misused it because all the cubes parts were deformed...
I'm going to try again without that, keeping your example at hand, thank you !

2yr

Hey, that's a very pretty scene. :)
I think the problem is conceptual rather than technical; it might be that the perspective of the tower's roof doesn't agree with the perspective of the rest of the composition.
It seems to me that the cone of the tower is angled in such a way that I'm seeing a lot more of the underside than I would be able to from the viewer's vantage point as you've defined it. Possibly adjusting the cone's angle so that less of the underside is showing might solve the problem?

2yr

Yes I agree, the tower perspetive looks different, although I still don't understand myself how I manage to get that. Of all the drawing it's this part that took me the most time just because I couldn't figure out how to do it properly.
I will do a full redraw, I think I wrongly understood one of the perspective rule I tried to use, which resulted in this. Even the basis seems off, it's supposed to be a circle, but it looks like a very stretched cylinder.
Thank you for your help :)

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2yr

short answer- the way you drew the red lines is "correct". I don't understand why you slanted the coned roof- and the longer answer involves understanding the limitations of linear perspective (which- gasp! isn't perfect). can you show the construction lines you used and why you angled the roof?

2yr

I was pessimistic, I only deleted the old inking, not sure this constructions lines are going to help you understand what I did wrong, as you can see it's messy

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2yr

I don't think I kept them :( but I will look when I'm in front of my desk. After seeing the end result, I already decided to redraw everything and was pretty pissed with myself, I may had have an emotional vengeful delete action ^^".
The way I proceeded is : I tried to draw 3 big cubes on top of each others, but using a tips I found to "calculate" a true square in perspective (and I most probably didn't understand it correctly).
At some point I remember I had trouble to figure out where was the center of each and how to have smaller cube, which is propably why nothing is aligned actually. I didn't used a center line to draw the tower, but the outer side of the first cube on the floor...
Thank you for your time and reply :)