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

[wizard509]

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.

Attachment 102804

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

I usually did 2 point because of the verticals. In 3 point they are not vertical. In 2 point you can see the same sides as you show in your 3 point example, it just depends on where you set your horizon. I admit that 3 point perspective in interesting and probably more realistic but 2 point is interesting also, and if you are doing it by hand it is so much easier. Finding the 3rd vp can be a real bugger if you want realism. It's so much easier to position it by eye to give the effect you want.

[wizard509]

Here is an example of one I did with a high horizon.

[Gare]

Hi Gary, it was not my intension to migrate or hi-jack the thread to perspective...Stygg

You didn't stygg, and I didn't say you did. I said the thread is migrating toward perspective and I'm all for that: it's just another aspect of Art, and it is relevatnt o our discussion about making a cube, all 6 of whose sides can be seen.

No, no, keep ity up. I'm truly enjoying seeing what you folks are inspired to create.

My Best,

Gary

[stygg2003]

Hi Gary, after viewing the image Frank posted about the faults in my cube image and his explanation of horizons, vanishing points and so on, I realized I had no idea what he was saying, the reason being, I have never drawn a cube or anything else using perspective lines from scratch, usually my cube starts with a square, then extrude then faces, no thought of how it will look on a final piece, ie, is it above or below an horizon, never gave any thought to all that because I had no idea what is involed to make an image look at least correct. So I gave myself a brush up on the above and at least I now know how to draw a cube from scratch and how different it looks in relation to its horizon position. Not attempted a three point cube yet but will do so. The image I've posted may not be spot on but it's more than I knew a couple of days ago.

Sorry to rant on,

Stygg

[wizard509]

You are doing well Stygg, however your use of the station point has me confused. The Station Point is the point where you are standing or more precisely where your eye is in relation to the view.
So you have a station point, a horizon line and a picture plane. If you have a plan and want to draw it in perspective, your horizon is where ever you want it, the station point is your eye, and all rays come from the station point projecting the points of the object to the picture plane then those points are vertically dropped to the horizon line in in 2 point perspective. Most of the literature on perspective shows the object touching the picture plane but it does not have to be. The picture plane is precisely located to a distance from the object so you can control the final size of your drawing.
I had been doing a tutorial on perspective but dropped it some time ago. It can get fairly complected if you have multiple objects and different levels in the scene. For sure you must pick place on the object being drawn and the heights of everything else uses that particular line as a reference. For instance if you have another (cube) that is not touching the primary cube, you use that particular line or face in some way to get the information to draw whatever additional objects you may have in your scene. The vanishing points are precisely located on the horizon based on the view. If any questions, just ask.

[stygg2003]

Thanks for the feed back Larry, much appreciated. I think I confused myself some what but the use of the station and diagonal
line was to help me be more precise with the bottom and side of the cubes, perhaps as you say there was no need for them and as you say "Never give up. You will never fail, you'll just find a whole lot of ways that don't work." Never the less I am enjoying this with never having drawn anything from scratch using these techniques and I certainly will ask Larry if I'm not sure about something.

Cheers Larry,
Stygg

[Gare]

Hi everyone—

Let's give the perfect formula for 2 and three point perspective a break for a while, because

1.) This can sometime be unsolvable geometry, because if you're trying for a camera-type angle, the lens of many cameras is not 50 to 55%, which is about equal to human vision, and

2.) I did a bonus challenge. Here's a composition of cubes, and at right are the dashed lines for the back faces, and they are accurate.



I set the nudge distance so one keystroke to the right, and the dashed lines will overlay on the drawing.

BUT...you might want to learn from these dashed lines instead of just using them to build the back faces of the cubes.

I want this to be an exercise in shading thew cubes. You can see the the lighting is coming from the right, because the shadow are casting on the opposite side. Now, this is not a perfect piece: I didn't bother to sock up all the control points so there's minor overlapping. But give some consideration to the transparency and color values, eh?

That was the other part of the tutorial!

My Best,

Gary
Xara file's attached.

[Gare]

somewhere, rotting away on a backup drive, i have a copy of bryce2, if you remember that
i used it once and hated its ui so much i never used it again

Bryce has been under the stewardship of several companies and I consider it Orphanware, unlike the fate of Poser when MetaCreations blew themselves up after a spending spree.

Bryce's companion programs under HSC Software, grew into holding of Fractal Design Painter, Carrera (which is the cheapest, most intuitive of 3D commercial software, KPT plug-ins, and a few more baubles. Corel snapped up KPT filters after the newly named MetaCreations, and DAZ took up the remainder. DAZ was originally called Zygote and contributed a lot of accessories and poses and stuff designed from Poser, but they has a severe disagreement which lead to DAZ creating their own environment, their own figures which are completely incomparable with Poser clothes and poses, and back to why Bryce sucks.

It was originally engineered by Eric Wenger (with help from Ed Muscgrave —now developing MojoWorld), and Benoit Mandelbrot. The funny thing is that Vue (d-Esprprit) kicks the daylights out of Bryce, from rendering time to breatakingly photorealistic clouds. It's prices in terms of features, from $100 to a thousand U.S. I think; here's the ironic part: Nicholas Phelps, living in France as well as Wagner, who lived only miles from one another, had no realization that the other was working on a terrain generator.

Bryce has stumbled and fallen itno the Poor Man's Vue, probably because the brilliant developers have moved on to more personal and lucrative things. Bryce feels as though the new versions are created by someone's 10 year old nephew at DAZ.

If you want a good start to 3D modeling, Blender is open source and free, you can do positively amazing things with it including fluid simulations,



but the learning curve is just as steep as a commercial modeling/animation program.

I'd suggest Art of Illusion a pretty straightforward modeling program that requires a little time to get on board, but the results can be seen like this:



The scene is a little "dark" for my sensibilities, but the thing does support ray-tracing, and produce acceptable, photorealistic scenes with a pretty straightforward UI.

MtyBest,

Gary

[theinonen]

Carrara is pretty good value for the money but Realsoft 3D is not much more expensive, has nicer user interface and is lot easier to work with.

I have both and must say I rarely even load Carrara because of the usual dark and depressing user interface and it also feels like it has been stiched together from several different applications, mainly Raydream studio and Amapi.

[Gare]

theionen—

Carrera was exactly Ray Dream Designer: it floundered, Corel licensed it for one version, dropped it, DAZ renamed it, and as far as I can tell, with the exception of being able to import Poser and DAZ figures, it's still not a place for a new, ambitious place to work. That's why I suggest Bryce and Art of Illusion, because "the heavies" are too expensive, and you'kk never learn to use more than 10% of its features. If anyone else has seen a good, free modeling program, please chime in here.

-g