Draw a realistic Cube, Cone or Sphere

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RM.
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Draw a realistic Cube, Cone or Sphere

Postby RM. » Mon Mar 14, 2011 9:54 am

Ok, maybe the 'fruit' competition was too much even for me. So this time, we are going to do something easier.
One rule only: no filters. Choose one from cube, cone and sphere and show us how good you are with Inkscape! :D
Hope you will enjoy!
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Simarilius
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Re: Draw a realistic Cube, Cone or Sphere

Postby Simarilius » Tue Mar 15, 2011 5:22 am

Cheating slightly as its something I did a while back

Image

its the end product of a tutorial I wrote, which can be found at

https://sites.google.com/site/johncliff ... ects=0&d=1

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Re: Draw a realistic Cube, Cone or Sphere

Postby RM. » Thu Mar 17, 2011 7:13 am

Good! Thank You for join in. :)
I'm doing a cube. First, second and third wip. Suggestions?

[Updating pictures]
Last edited by RM. on Wed Mar 25, 2015 10:41 pm, edited 1 time in total.
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Re: Draw a realistic Cube, Cone or Sphere

Postby Simarilius » Thu Mar 17, 2011 7:31 am

Great start, the front face needs something tho, feels like its floating at the minute. the shadow along the bottom of it makes it look like its lifted too.

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Re: Draw a realistic Cube, Cone or Sphere

Postby RM. » Fri Mar 18, 2011 8:01 am

Also the shadow seems too big. And now the big question. :lol: Right part too dark or left part too light?

[Updating picture]
Last edited by RM. on Wed Mar 25, 2015 10:40 pm, edited 1 time in total.
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Re: Draw a realistic Cube, Cone or Sphere

Postby prkos » Fri Mar 18, 2011 10:34 am

Right part too dark, there's too much diffuse lighting to have an open surface so dark.
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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Fri Mar 18, 2011 1:29 pm

Aarrrrgh! I'm sure I replied to this days ago.....
In any case, this sphere was my first attept at a 3d simulation:

Image

There's no ground or surface or shadow, because I intended to use it as something like a planet -- suspended in space, I guess.

Gosh Sim, I wish I had found your tutorial back then. The only tuts I could find at the time were for creating special effects, like metal, glass, shiny, etc. I just wanted plain 3d. I ended up finding a tutorial where the sphere was just small part of a much longer tutorials. It wasn't quite what I wanted either, but it gave me the tools to eventually get what i wanted....or close enough.

But for this challenge, I think I'll do something different. Maybe either a sphere, for which I want to try to use LPE Hatches, to do the shading, etc. OR I'll try a cone -- TRY, because as we know, Inkscape cannot make a wedge-shaped gradient which would be necessary for the cone. So that certainly represents a challenge, lol!

Ok then, I'm off to fire up Inkscape, to learn what I can learn, and create :D

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Re: Draw a realistic Cube, Cone or Sphere

Postby spaventapasseri » Fri Mar 18, 2011 9:43 pm

I want to partecipate as well.
Here my first wip

Image
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Re: Draw a realistic Cube, Cone or Sphere

Postby GAngus » Fri Mar 18, 2011 11:18 pm

Here's my attempt, if I can do the link thing properly.....

Image

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Re: Draw a realistic Cube, Cone or Sphere

Postby marydonata » Sat Mar 19, 2011 1:18 am

I draw a Sphere, this my image:
Image

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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Sat Mar 19, 2011 2:47 am

Wow guys!
Nice work, and quick too!

spaventapasseri, :lol: nice Rubik's cube! Are you using the axonomic/isometric grid, or just "eyeballing it" (American expression meaning that you rely only on your vision to draw it)? That's gonna be awesome when it's finished!

marydonata, I like how you use the grid to emphasize the depth/3D effect! The sphere I'm working on has many crescents for shading, etc. Did you use one of the grid-making extensions, or draw the lines by hand? .....ohh wow! I just thought of a neat effect to play with on my sphere, inspired by yours. I'm using this little challenge as an opportunity to learn about the Hatches LPE, so I'm wondering if the hatch lines could be used in a similar way? I'll definitely post my results when I have something ready. I don't even have a first wip yet.

RM.
Right part too dark or left part too light?

I think it looks like the box/cube is under....or almost right beside a strong light, because of the heavy shadow on one side only, or in other words because of the strong contrast of light/dark. I'm not saying that's a bad thing, it's just what I see. I like how you used the gradient (or maybe blur) on the side facing us. It's a nice touch and very effective. I'll have to add that trick to my repertoir (sp?) :D

GAngus, I like how you use the light colored stroke with the darker fill. And I think I see a gradient in your shadow, which is nice. I tend to make shadows solid, but that's really not how things are in reality. Is it just me, or does the perspective seem "off" to anyone else? Or is it just my whacky brain, lol, I do struggle with perspective :roll:

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Re: Draw a realistic Cube, Cone or Sphere

Postby marydonata » Sat Mar 19, 2011 6:36 am

To make the grid, I used Tiled Clones, I draw a circle, and then in the Clone Tiling dialog I put Rows,Columns 1x10, Symmetry Simple translation, Scale per column -10. Then I draw a path in the middle. I duplicated the outcome, and then rotated it 90°.
Then I grouped all the paths and put them on the first circle, that I had still filled with a gradient.

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Re: Draw a realistic Cube, Cone or Sphere

Postby RM. » Sat Mar 19, 2011 7:53 am

Brynn, just blur, i'm Master Blur :lol:
There are some good spheres and balls on morguefile.com, if someone needs inspiration.
Ok ok too dark.. trying to fix things a lil bit.

[Updating picture]
Last edited by RM. on Wed Mar 25, 2015 10:41 pm, edited 1 time in total.
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Re: Draw a realistic Cube, Cone or Sphere

Postby Simarilius » Sat Mar 19, 2011 9:09 am

One more from a while back too.

Image

Again, from a tutorial I wrote a while back...
http://simarilius.wordpress.com/2006/07 ... e-shadows/

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Re: Draw a realistic Cube, Cone or Sphere

Postby GAngus » Sat Mar 19, 2011 10:57 am

@brynn, "Is it just me, or does the perspective seem "off" to anyone else?"

Thanks for the kind crits... I could have spent more time on it actually...

Yeah, after I finished the basic cube (started with the 3D tool) and added the shadow, with a little blur and YES a small gradient....
I decided that it looked too "alone" just sitting there in space, so I took the bezier tool and just eye-balled a flat surface under it,
the perspective of which, is not in mathematically congruent with the cube object.

I recall having to adjust it a lot of times and figured, in that it would be cropped off by the border, it wouldn't matter too much.
I should have known better, that someone here would pick up on it... i'm busted !!

It was done as an afterthought, just to give the piece some degree of a finished look.

So/but your you are right, it probably IS a little "off" . . . 'good eye' !!!
I should pay more attention to detail...... thanks

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Re: Draw a realistic Cube, Cone or Sphere

Postby RM. » Sun Mar 20, 2011 7:48 am

Don't worry GAngus we are here for learn! ;)
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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Sun Mar 20, 2011 11:45 am

Ah, well then now it is my turn to put my stuff out there, lol.
Since I had already done my own practice with the realistic sphere some time ago (that I posted above) I decided to use this as an opportunity to learn and play with the Hatches LPE. (although I realize that shading by hatching isn't exactly realistic) Something definitely seems "off" to me about the results, but I'm not sure what it is. Hopefully you all can comment.

I was thinking about using a gradient on the hatches. But I've always admired the kind of pencil or charcoal art work that's entirely done with hatching, and those certainly don't use gradients. However, I think it must take a lot more skill than I have. But you have to start somewhere, right? Anyway, maybe if I vary the thickness of the hatches more?

Actually, now that I'm about to post it, it looks like I might have accidentally varied the bottom edge of one of the lower hatched crescents. There's too much light green showing through around the bottom edge. But anyway, comments appreciated :D

On the first one, I made the edges of the hatches smooth. Then I duplicated, and jittered the edges of the 2nd one.

Image

Meanwhile, I'm intrigued with marydonata's sphere. You said you used tiled clones? What object was cloned and tiled? The vertical and horizontal lines/paths? That's amazing! I had no idea tiled clones could do that!

RM. wrote:Don't worry GAngus we are here for learn!

Yeah, feel free to let loose on mine -- I love to learn! :lol:

Sim, nice cylinder! Do you think you could do a cone, and simulate a wedge-shaped gradient....somehow? Maybe using interpolate, maybe with tiled clones? I think I might try it....

RM., yes, the light source is not so close any more. I like it!

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Re: Draw a realistic Cube, Cone or Sphere

Postby spaventapasseri » Sun Mar 20, 2011 4:25 pm

brynn wrote:Wow guys!

spaventapasseri, :lol: nice Rubik's cube! Are you using the axonomic/isometric grid, or just "eyeballing it"

Hi brynn I used the axonomic grid, I will put soon the next wip ;)
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Re: Draw a realistic Cube, Cone or Sphere

Postby RM. » Mon Mar 21, 2011 9:00 am

brynn wrote:Yeah, feel free to let loose on mine -- I love to learn! :lol:

And i love your big comments :lol:
Umm, the first one looks better, maybe the shadow needs to be darker?
What is LPE :?:
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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Mon Mar 21, 2011 11:56 am

What is LPE

Live Path Effects -- probably slightly different under Italian translation.... Huh, I tried Google translation, but it's not working for some reason, right now. I tried the new feature (well, new to me anyway) where you can listen to the translation. So it pronounces the English words as if they were Italian, lol!

I think I'm going to search for some artwork done with the hatchmark style, to get some ideas.

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Re: Draw a realistic Cube, Cone or Sphere

Postby spaventapasseri » Mon Mar 21, 2011 12:04 pm

Hello Rm, Live Path Effect are the "Editor effetti tracciato" and the hatches are the "scarabocchi" you can use these and various type of effect on your path.
Just Maisc+Ctrl+7 on you keyboard and try all of them.

Image


stella con effetto scarabocchio grezzo.- stars with hatches
Image
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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Mon Mar 21, 2011 10:13 pm

Ok, here is more like what I wanted to do:

Image

I think to be really cool, I would need to have more incrementally sized crescents. But I think understand what would I need to do, and am fairly satisfied with this. I'm anxious to get on with the "cone" challenge though, so this is probably my final product on the sphere. Comments welcomed :D

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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Tue Mar 22, 2011 1:18 am

Image Oh wow, I can't believe my first idea worked so well! I thought I was going to have to work all kinds of magic, but it turns out that blur and interpolate are the only magic needed. Also needed is a good eye for color, which I don't quite have. But this is close enough to get the idea across :D

All Inkscape:

Image

The one on the right is kind of the raw product -- all interpolated and clipped, but not blurred. So if you look closely, you can see the individual lines/paths. And you cans probably see the area where my color choice made for a rough transition in my spoofed gradient ("gradient"). But the light is supposed to be coming from behind the cones, and off to the left. On the right, it only took 5.0 blur to make it fairly realistic.

I'm gonna write up a quick tutorial, which I will edit a link in here when it's finished and posted. But basically, I drew the cone shape, and 5 straight lines, all with starting point at top of cone, and ending points, each spread out evenly across the bottom. Then I interpolated between each line (creating 4 groups of 20 lines/paths). Then I duplicated the original cone, to use as a clipping path, and clipped all 4 groups to the cone shape. (The original lines have to be all longer than the cone boundary, for a reason that you will quickly learn faster than me trying to explain.) Then blur, and done :D

Comments?

Edit -- omg, now I can finally animate my avatar! I tried it before, with using a lot of magic, and faking the gradient turning a corner, but now, I think I can do it, lol!!

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cone shadow geometry

Postby brynn » Wed Mar 23, 2011 12:12 pm

Ok, I tweaked the interpolated lines a bit, because I thought the shading looked darker near the top of the cone, which I don't think is realistic. Also, I think I got a better color choice on the left side now.

Now, I've decided to put a shadow on the suface on which the cone is sitting. But I'm having trouble getting the right placement for the shadow that falls on the surface on which the cone sits. Here's a screenshot. The shadow's red at the moment, while I work with it.
Image
I started on the shadow by duplicating the original cone shape, flipping horzontal, and snapping the nodes at the base of the cone (there's a red horizontal guide also snapped to those nodes, partly for clarity). So that's perfect, if the light were directly behind the cone. But it's not, it comes from behind, and to the left. So I thought great, I'll just drag the node at the shadow's apex, over to the right! And you can see the result. The problem is the area indicated by the black arrow. That part of the cone is throwing no shadow. That's definitely not realistic, lol!

And I realize that I could just "eyeball it", to set the shadow. But I'm curious how this should work geometrically. I think with the light coming from where it does, the outer edges of the shadow should not connect where the nodes are. They need to connect to the points of a line perpendicular to the direction of the light, where the line intersects with the circumference of the circle at it's diameter.

So I drew out 2 guides and placed them so that they intersect at the center of the circle (ellipse) at the base of the cone. Then I turned the shadow (which was the duplicated cone) into a triangle, by deleting the node between the 2 base nodes, and making it a straight segment. So now this new straight segment, the base of the new triangle, actually represents the diameter of the circle. I dragged the shadow's rotation center to the center of the circle, so that it rests on this segment (at exactly the center). (Since I had drawn the original cone using snapping and a grid, I knew it was exactly symmetrical. Otherwise none of this would work.) Here's an illustration:
Image
So now when I rotate the triangle, it rotates the diameter of the circle that's at the base of the cone. (I indicated that diameter by highlighting the base of the triangle with a black line.) I estimate that line now is perpendicular to the direction of the light, and where it intersects with the circle (ellipse) is the point where the edge of the shadow should start. So I just need to snap the corner node of the shadow (the one on the left) to that intersection.

For the placement of the right node, I see that the intersection of the other end of the diameter and circle is behind the cone (from the viewer). Therefore, the original base node of the cone should work for the right side. So all that's left for me now is to drag the apex of the shadow a little further to the right, and maybe down some. Then give the shadow some appropriate dark color, and some blur.

Now after all that, I'm wondering if anyone has any ideas for a quicker, more exact, or easier way to place the shadow. I know I've seen some brilliant solutions to geometric problems in this forum, and I always learn so much. So certainly there's no urgency -- I just thought I'd put it out there, to see if anyone has other ideas :D

All best Image

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Re: Draw a realistic Cube, Cone or Sphere

Postby brynn » Wed Mar 23, 2011 12:34 pm

Hey Simarilius,
I was just reading your tutorial on the sphere/marbles. They seem so familiar to me, for some reason, and I finally remembered what they were reminding me of. The colors and style seem nearly identical to the...tiles or game pieces in this flash game that I enjoy. Here's a screenshot:

Image

So I'm thinking either you made the game, or whoever did, used your tutorial for part of the graphics!
You think...or just coincidence?


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