I am doing scientific engineering with SketchUp, and even if there are some features missing, I managed to acheive some complex models with the basic free version and without plugins ... Then as TIG said, you may even improve your SU experience with all the plugins available ...
one example I did with SU :

I personally use the "DownThemAll" plug-in for firefox, it usually works fine, However, I have never tested it within a Google search ... google usually provides links to the webpages and not to the images themselves ...

very funny indeed !!!

Selectionne ton composant > COPIER
Nouveau modèle > COLLER

This latter more looks like e-paper than a rollable laptop. And electronic paper has been on the market for a few years already

I am amazed !! Great Job !

For bycicle chains, the size of the wheel and the number of teeth are closely related. When you have your tooth element, make it a group end save it aside. When you create the next wheel, calculate it diameter precisely, copy your tooth group to that new wheel, explode the group to intersect it with the wheel and copy it the correct number of times. It should run ...

He already decided his favorite color was "RAINBOW" ;o)

And anyway, I think we are enough english-speaking persons to help you os time-to-time basis, but right now, nothing to say but thanks for the efforts in writing in our so complicated language, you are probably doing better in French than I am in English !

I think one of the most suitable options would be to use the Sandbox 'contour' option.
I'v used it in one of my projects and it allows very nice shapes

A savoir, quand tu as un groupe, si la couleur est celle par défaut et que tu lui appliques une couleur, elle sera "transférée" à l'interieur du groupe, par contre, si les objets dans le groupe ont une texture propre, elle ne sera pas remplacée !
J'ai déjà été confronté à ce phénomène ;o)))

L'interface est en anglais ...
la rusticité est bien au rendez-vous, il reste maintenant à voir ce que ca donne en efficacité ... je viens de subir mon premier plantage ce qui n'est pas de bonne augure, mais on verra ...

Unfortunately, I think proper animation does not take shadows into account. but the moves are covered by proper animation alone. So SketchUp does not "see" the part moving.

couldn't you create a section plan that would hide all unneccesary parts ?

You can also create a circle, the select only some "segments" and resize them with the rescale tool to change the local curvature

Some are really really very nice !! Congratulations

suffit de mettre les surfaces planes légèrement obliques ...

a part créer un composant VIS à placer là où il te les faut, je ne sais pas trop ...
Voila ce que j'ai fait pour un de mes anciens projets ...

Muse FSO Holder.skp

il y a surtout proper animation (gratuit) qui fonctionnera très bien pour cette application. Couplé à smooth animate, ca fera un résultat rapide à obtenir et correct !

I am just amazed !!!!