June 2014 Video Tutorial - Creating 3D Semi-Transparent Cubes in Xara

[Egg Bramhill]

I believe Frank is saying that the cube looks like it's floating above the landscape, and therefore wouldn't have a shadow, at least in that position. If the cube is on the surface then the perspective is at odds with the background perspective.

[Big Frank]

stygg your hot stuff image would have worked for me
had it not been for the little squares on the bg image (perspective again)
your cube looks to be floating or tilted on end so the shadow wouldnt/shouldnt be there
it is either an optical illusion or the perspective of the two planes is wrong
the two planes being one the cube two the bg

i thought id try and draw what i mean
i hope you can see on the attached that the cube has two vanishing points
this creates the first horizon
the little squares on the background are so blurred its not easy to find their vps
but having taken four squares you can see a pattern
their vps give us a horizon that doesnt come close to the cubes
and our eyes therefore tell us that the cube and the background are not on the same plane
you can do this exercise yourself with any composite image
i'm not sure if ive explained myself at all actually

[stygg2003]

Thanks for your explanation and diagram Frank, I think I've got it, I think I need a serious tut. or vid. on this perspective subject and from your posts, your just the man to do one

@ Egg - thanks for your explanation too Egg and you also would be a good candidate for a tut. or vid.

I'm pushing my luck here now but thanks once again both of you.

Stygg

[Big Frank]

im not really up to doing a tut
hope to be better soon
theres loads of info on the web
google is your friend

[stygg2003]

Did what you suggested Frank and had a look round the Web for Perspective help. I found this one which is one
point perspective, nothing to difficult but is a place to start, I did the door, rug and window with frame. There's a few more things to draw in it yet, such as sky light, I've also got to add the rest of the orthoganals,
horizontal and vertical lines yet which I will need for ceiling and floor perspective, so I'm pleased with this start on perspective drawing.

Stygg

[Gare]

@ Big Frank—

Frank, I thank you so much for opening up the issue of math perspective to help complete drawings of scenes with dimension. It's really helped boost the activity here! Filippo Brunelleschi, and then Leonardo DaVinci laid the groundwork for a very important aspect of artistic creativity, and I'm glad to see it's still alive and well.

@Egg— I'd swear I have a Dark Side of the Moon Pink Floyd T-shirt in my closet that looks like your attack of the pyramids piece! :) Nice work!

My Best,

Gary

[Egg Bramhill]

Hi Gary, that must be tweaking my subconscious mind too

[stygg2003]

Hi every one, just an update to #53. I finished adding all the lines to the one point perspective grid, it maybe not 100% perfect but it's a start at least, I think this grid will be really useful for my understanding of perspective.

Stygg

[Gare]

Okay, as long as this thread is migrating into perspective, there are two things I'd to offer:

1.) If your hypothetical camera on the scene uses something other than a 50 to 55mm lens—such as a 28mm wide angle—perspective lines are going to bend and throw your calculations off because a sort of hyper-perspective is being viewed, angles our naked eyes are not familiar with.

2.) I did a quick drawing of examples of 1, 2, and 3 point perspective, with the backsides represented as dashed lines.



At some point, you might want a little artistic sensibility leak into this geometric true-ism. 1 point perspective art can be interesting, like standing on a railroad track (while there is no train coming), and photographing straight down the vanishing point, the point where the rails seem to converge. Other than that, I'm hard pressed to think of a visually interesting 1 point perspective piece.

I usually aim for 3 point because that isa the maximum number of viewable sides without animating the object, but 2 point is useful and can be quite interesting if you make the sides semi-transparent.

My Best,

Gary

[stygg2003]

Hi Gary, it was not my intension to migrate or hi-jack the thread to perspective, with Frank pointing out the faults in my image, it started from there. The image and file you have just posted is what I'd thought I'd brush up on, hence the one point grid I made to make a start from that and then two and three, it's not a strong point perspective for me so thought I'd brush up a little. The artistic sensibility and perspective true-ism would be a bonus for me if I could combine the two with some balance so to speak.

Stygg