Hi all

I'd appreciate some help on a small issue - I'd like to take any 2D shape (as a path, not a bitmap - lets take a bicycle as and example), and apply it to a 4-node deformation envelope, so that I can then simulate changing perspective by pulling out (or pushing in) any or all of the envelope's nodes. Now it's true that I could use the Envelope or Perspective extensions, but they appear to execute a one-time-only transformations. In other words, I would like to have the freedom to carry on tweaking the new perspective - even returning to the original shape if needed. It might be that this functionality exists within Inkscape and I haven't found it yet, in which case I apologise. Any ideas or pointers much appreciated.

D

Welcome to InkscapeForum

I'm not sure if I understand what you want to do. What I think you might mean, I don't know the right words to describe it, but Inkscape doesn't have it. But Inkscape might have something that will work, although I'm still not entirely clear.

There are both Envelope Deform and Perspective extensions. But you're right, they just perform their function once. If you want to change the angles, you have to draw a new skeleton path. However, there's an Envelope Deform LPE (Live Path Effect) which is sort of like live editing. Not exactly what I think you might be looking for, but sort of. Here's the manual info on it: Basics - Help menu > Tutorials
Manual - Inkscape: Guide to a Vector Drawing Program
Inkscape Community - Inkscape FAQ - Gallery
Inkscape for Cutting Design

brynn wrote:What is the situation where you need this kind of functionality?

Everytime ! SVG definitively lacks a perspective transform.

Designing things such as an hard drive
http://hezral.deviantart.com/art/hard-d ... -131250904

is overcomplicated because the lack of a (friendly) perspective tool

However, there's an Envelope Deform LPE (Live Path Effect)

ah yes but that squeezes the sides, rather than pulling or pushing the corners.

I think that Inkscape does lack a decent perspective editor, a bit annoying.

As for why I might want to use it, I want to take 2d images without perspective and apply a vanishing point (or points) to the X and Y viewpoints.

One of the most serious omissions in SVG from an artistic point of view, IMO, but unfortunately rejected for SVG2 as well:

http://www.w3.org/Graphics/SVG/WG/wiki/ ... transforms

Well I would say that the Envelope Deform LPE is not really a good substitute for perspective. In some cases, it can be used to fake perspective, but it's never a true perspective, unless you've done some kind of complex calculations, lol.

You're right, to tweak perspective, you have to go back and tweak the skeleton path used in the extension. There is not a live edit option for that. Some of the extensions have a Live Preview option, which would be at least a minor improvement. But as far as I know, Perspective does not have a live preview. It actually might not be very hard to give it a live preview, but I don't know if it's ever been requested (officially).

I don't understand the comment about the Envelope Deform LPE squeezing the sides. You can move the nodes of the "bend paths" in any direction, and if you move them outwards, then it stretches the object, rather than squeezing. But note that for moving the top right corner of an object, you have to move the top node of the right bend path, AND the right node of the top bend path.

My best wish for the LPE, is for all the bend paths to be visible and editable at the same time, instead of one at a time.