Animation, 3D development

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Just ask them. KDAB website, twitter, facebook.

Naveen_D

@Wieland Ok thank you :)

Naveen_D

Hi,
can anyone help me how to create and .obj object for 3D rendering and how to load it and display in Qml?

for example, if i want to display on 3D car module how to do that ?
Thanks in advance

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Hi!

@Naveen_D said in Animation, 3D development:

can anyone help me how to create and .obj object

You don't do that yourself but either buy ready-made models or pay a digital artist to create one specifically for you. Google "buy 3d models".

how to load it and display in Qml?

See Mesh QML Type,

Mesh {
    id: mesh
    source: "cars/BMW/i8.obj"
}

Naveen_D

This post is deleted!

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@Naveen_D said in Animation, 3D development:

is there any open source from where i can take 3D models

Maybe use google search?

mrjj

I used from this place
https://www.turbosquid.com/Search/3D-Models/free/obj

Maybe this one :)
https://www.turbosquid.com/3d-models/3d-mercedes-benz-sls-amg-model/644946

Naveen_D

@Wieland i tried with the following code:

import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Extras 2.0


Mesh {
    id: mesh
    source: "qrc:/seat_leon.obj"
}

but didn't get the output. is there anything else i need to do for getting the output ?

Naveen_D

@mrjj ya i got that thank you

? Offline

Here's an almost minimal example in QML:

GearEntity.qml

import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Input 2.0
import Qt3D.Extras 2.0

Entity {
    id: gearEntity

    Mesh {
        id: gearMesh
        source: "qrc:///assets/gear.obj"
    }

    Transform {
        id: gearTransform
        scale3D: Qt.vector3d(45, 45, 45)
        rotation: fromAxisAndAngle(Qt.vector3d(1, 0, 0), 45)
    }

    PhongMaterial {
        id: gearMaterial
    }

    Entity {
        id: torusEntity
        components: [ gearMesh, gearTransform, gearMaterial ]
    }

}

RootEntity.qml

import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Input 2.0
import Qt3D.Extras 2.0

Entity {
    id: rootEntity

    Camera {
        id: camera
        projectionType: CameraLens.PerspectiveProjection
        fieldOfView: 45
        nearPlane : 0.1
        farPlane : 1000.0
        position: Qt.vector3d( 0.0, 0.0, 40.0 )
        upVector: Qt.vector3d( 0.0, 1.0, 0.0 )
        viewCenter: Qt.vector3d( 0.0, 0.0, 0.0 )
    }

    FirstPersonCameraController { camera: camera }

    components: [
        RenderSettings {
            activeFrameGraph: ForwardRenderer {
                camera: camera
                clearColor: "transparent"
            }
        },
        InputSettings {}
    ]

    GearEntity {}
}

main.qml

import QtQuick 2.7
import QtQuick.Window 2.3
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3
import QtQuick.Scene3D 2.0
import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Extras 2.0

ApplicationWindow {
    visible: true
    visibility: Window.Maximized

    Rectangle {
        anchors.fill: parent
        gradient: Gradient {
            GradientStop { position: 0.0; color: "blue" }
            GradientStop { position: 1.0; color: "grey" }
        }
    }

    Scene3D {
        id: scene3d
        anchors.fill: parent
        focus: true
        aspects: ["input", "logic"]
        cameraAspectRatioMode: Scene3D.AutomaticAspectRatio
        RootEntity {}
    }

    Button {
        text: "Exit"
        onClicked: Qt.quit()
    }
}

Naveen_D

@Wieland thank you... i got the output.
I have one doubt, in the output when i try to rotate the object it is not rotating in the same place, instead the camera is rotating(i guess), is there any way to fix the camera and rotate the object in 360 deg ?
Thank you

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That's just how FirstPersonCameraController works. You could either implement your own camera controller or - instead of moving the camera - dynamically change gearTransform.

Naveen_D

This post is deleted!

Naveen_D

@Wieland

You could either implement your own camera controller

How i can develop my own camera controller is there any example for this ?

Naveen_D

@Wieland
I have made few changes in the code shared by you, what i have done is, Using blender software i have sliced the car obj for few diff parts like door, wheel, window, bonet etc and i have rearranged the whole car by adding the car parts in the code.
Now when i try to add some animation for each of the part, for example i want the door to open and close as usual as it does normally, but what is happening,the door part is taking car body as the center and it is rotating inwards in the given angle. how can i change this to make it work properly.
here is the code,

import Qt3D.Core 2.0
import Qt3D.Render 2.0
import Qt3D.Input 2.0
import Qt3D.Extras 2.0
import QtQuick 2.5

Entity {
    id: carFrontLeftDoorEntity

    Mesh {
        id: carFrontLeftDoorMesh
        source: "qrc:/Meshes/Car_FrontLeftDoor.obj"
    }

    Transform {
        id: carFrontLeftDoorMeshTransform
        scale3D: Qt.vector3d(1.5,1.5,1.5)
        rotation: fromAxisAndAngle(Qt.vector3d(1, 0, 1), 30)
        rotationY: 0

        SequentialAnimation {
            loops: Animation.Infinite
            running: true
            NumberAnimation {
                target: carFrontLeftDoorMeshTransform
                property: "rotationY"
                from: 0; to: 15
                duration: 2000
                easing.type: Easing.InOutQuad
            }
        }
    }

    PhongMaterial {
        id: carFrontLeftDoorMeshMaterial
        ambient: Qt.rgba( 0.0,0.0,0.0, 0.6 )
        diffuse: Qt.rgba( 0.3, 0.0, 128, 0.2 )
    }

    Entity {
        id: carFrontLeftDoorMeshtorusEntity
        components: [ carFrontLeftDoorMesh, carFrontLeftDoorMeshTransform, carFrontLeftDoorMeshMaterial ]
    }
}

this i have added in the gearentity.qml as separate part.

Entity {
    id: gearEntity

    CarRawBody{}

    CarFrontGlass{}

    CarBonet{}

    CarDikki{}

    CarFrontLeftWheel{}

    CarRearLeftWheel{}

    CarFrontLeftDoor{}

    CarRearLeftDoor{}

    CarFrontLeftWindow{}

    CarRearLeftWindow{}
}

Naveen_D

hi, any updates on the above query ?
Thank you

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Hi! Sorry, that it already just too complex / incomplete for me to test and help with. Can you boil it down to a simpler question or a minimal runnable example that I - or anyone else who reads this - can use to reproduce the issue?

Naveen_D

@Wieland ya sure.. i will reproduce it and post the example code..
Can you please guide in the following issue also
Thank you.
https://forum.qt.io/topic/84633/camera-rotation-around-a-mesh

Naveen_D

@Wieland Hi,
I have few doubts regarding rotating an object in 3D,
For ex, i have a car model, which i have sliced in blender, to get door as a separate object and whole car as a separate object, i have exported both as .obj files and i have assembled them in the code.
Now what is happening, when i try to rotate the door which is separate object using number animation, it is rotating with respect to car's origin not w.r.t to door's so, i want to rotate it based on it's own axis or origin. not w.r.t car's origin.
I have tried the following code but didn't get the excepted result.

    // Car front door //
    Mesh {
        id: carDoorMesh
        source: "qrc:/Meshes/CarFrontDoor_modified.obj"
    }

    PhongMaterial{
        id: carDoorMaterial
    }

    Transform {
        id: carDoorTransform
        property real userAngle: 0.0

        matrix: {
            var m= Qt.matrix4x4();
            m.translate(Qt.vector3d(0.501096,1.5006,1.78036))
            m.rotate(userAngle, Qt.vector3d(0,1,0))
            m.translate(Qt.vector3d(-0.501096,-1.5006,-1.75036))
            return m
        }
         NumberAnimation on rotationY {
                    to: -45
                    duration: 1000
                    running: true
                }
}

i got the respective values from blender.
Any guidance is appreciated
Thank you.

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@Naveen_D No offense, but this has nothing to do with Qt really but only with your lack of a basic understanding of how transformation matrices work. Seriously, get a book on linear algebra or you'll never get this to work.